Battery pack and electric equipment

Abstract

The invention discloses a battery pack and electric equipment, the battery pack comprises a bottom plate and a plurality of batteries arranged on the bottom plate along a first direction, each battery comprises a metal shell, the metal shell comprises two oppositely arranged first wall parts, two oppositely arranged second wall parts and a bottom surface, the area of the first wall parts is larger than that of the second wall parts, and the first wall parts and the second wall parts are arranged on the bottom surface. The first wall parts of two adjacent batteries are oppositely arranged, and the outer surfaces of the first wall parts are provided with insulating layers; the bottom surface is provided with a first exposed area; the insulation paste comprises a first part and a second part, the first part is arranged between two adjacent batteries, and the second part is arranged between the first exposed area and the bottom plate; the insulating layer and the insulating paste meet the condition that [(2D1 + D2) / 2L] H is greater than or equal to 0.001 mm and less than or equal to 2.5 mm, D1 is the thickness of the insulating layer in the first direction, D2 is the thickness of the first part in the first direction, L is the length of the battery in the first direction, and H is the distance between the top end of the first part and the top surface of the bottom plate.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a battery pack and an electrical device having the battery pack. Background Art

[0002] A battery pack can be used, for example, to store or provide electrical energy. A battery pack often includes multiple batteries, which are electrically connected in parallel or in series to achieve the energy or voltage requirements of the battery pack.

[0003] When multiple batteries are assembled into a battery pack, they are placed in a corresponding casing, and the bottom surfaces of the batteries are directly bonded to the bottom plate of the casing. The provision of an insulating layer around the outer periphery of the battery metal casing weakens the bonding strength between the bottom of the battery and the bottom plate, leading to separation between the battery and the bottom plate. By exposing the bottom surface of the battery casing and bonding the casing with an adhesive layer, the connection strength between the bottom surface of the battery and the bottom plate is improved, preventing the risk of failure of the connection structure between the batteries due to separation of the two. However, this arrangement creates a safety risk of short circuits between adjacent batteries. Summary of the Invention

[0004] In view of this, the present invention aims to provide a battery pack and an electrical device having the battery pack, aiming to at least solve the problem of easy separation between the battery and the bottom plate of the box.

[0005] In one aspect, the present invention provides a battery pack, comprising a base plate; a plurality of batteries arranged and fixedly disposed on the base plate along a first direction, wherein each battery comprises a metal shell, the metal shell comprising two first walls disposed opposite to each other, and two second walls disposed opposite to each other, the area of ​​the first wall being greater than the area of ​​the second wall; the first walls of two adjacent batteries of the plurality of batteries being disposed opposite to each other, and the outer surfaces of the first walls being provided with an insulating layer; the metal shell further comprising a bottom surface disposed toward the base plate, the bottom surface being provided with a first exposed area; insulating adhesive comprising a first portion and a second portion, the first portion being disposed between and fixedly connecting two adjacent batteries, the second portion being at least partially disposed between the first exposed area and the base plate and fixedly connecting the battery and the base plate; the insulating layer and the insulating adhesive satisfy the following requirements: 0.001mm≤[(2D1+D2) / 2L]*H≤2.5mm.

[0006] Wherein, D1 is the thickness of the insulating layer in the first direction, in mm, D2 is the thickness of the first part in the first direction, in mm, L is the length of the battery in the first direction, in mm, and H is the distance between the top of the first part and the top surface of the base plate, in mm.

[0007] In another aspect, the present invention provides an electric device comprising the battery pack as described above.

[0008] According to the battery device and electrical equipment provided by the present disclosure, an exposed area is provided on the bottom surface of the metal housing, and the metal housing and the bottom plate of the housing are directly bonded together with insulating adhesive to enhance the connection strength between the batteries and the bottom plate. The batteries are arranged along a first direction, thereby improving the overall internal space utilization of the battery. Furthermore, the thickness of the insulating layer and the insulating adhesive in the first direction, as well as the distance between the insulating adhesive and the bottom plate, are appropriately set to satisfy the formula 0.001mm≤[(2D1+D2) / 2L]*H≤2.5mm. Within this range, the electrical safety between adjacent batteries is improved, avoiding safety risks such as short circuits between adjacent batteries. Furthermore, the expansion of adjacent batteries along the first direction, which could result in insufficient expansion space and lead to high internal pressure and the risk of thermal runaway, resulting in battery explosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0010] Figure 1 FIG. 1 is a top view of an exemplary battery pack according to the present invention.

[0011] Figure 2 for Figure 1 A partial schematic diagram of the BB section view.

[0012] Figure 3 for Figure 2 A schematic diagram of the structure between any two adjacent batteries.

[0013] Figure 4 for Figure 2 Schematic diagram of the structure in which the barrier between any two adjacent batteries is fixedly connected with the insulating glue.

[0014] Figure 5 for Figure 2 Schematic diagram of a structure in which there is a gap between the barrier and the insulating glue between any two adjacent batteries.

[0015] Figure 6 A schematic diagram of the structure of an exemplary battery.

[0016] Figure 7 A front view of an exemplary battery.

[0017] In the figure, 100. Battery pack; 10. Bottom plate; 20. Battery; 21. Insulation layer; 22. Battery cell; 23. Metal shell; 231. First wall; 232. Second wall; 233. Bottom surface; 24. Post; 30. Insulation glue; 31. First part; 32. Second part; 40. Barrier; 50. First spacer; 60. Second spacer. DETAILED DESCRIPTION

[0018] In a related technology, to address the issue of mutual insulation between multiple batteries within a battery pack, an insulating film or coating is applied to the sidewalls, or bottom surface, of the battery casing. When the multiple batteries are assembled onto a base plate, the insulating film or coating corresponding to the bottom surface of the casing is bonded to the base plate using structural adhesive. In other words, the bonding relationship between the battery and the base plate becomes that between the insulating film or coating and the base plate. During operation, the connection between the bottom surface of the casing and the insulating film or coating often fails, which directly leads to separation between the battery and the base plate.

[0019] In order to solve the above problems, the inventors have made many attempts. First, the inventors found that it is possible to not provide an insulating film or insulating coating on the bottom surface of the shell, that is, to directly bond the bottom surface of the battery shell to the bottom plate. However, this attempt will lead to the problem of increased risk of insulation failure between adjacent batteries. The inventors found that the insulation glue can be used as structural glue, and the insulation glue can be made to meet certain size requirements to solve the problem of insulation failure between adjacent batteries. Finally, the inventors creatively proposed the following technical solution: By providing an exposed area on the bottom surface of the metal shell and directly bonding the metal shell to the bottom plate of the box with insulating adhesive, the connection strength between the battery and the bottom plate is improved. The batteries are arranged along the first direction, improving the overall internal space utilization of the battery. The thickness of the insulating layer and the insulating adhesive in the first direction, as well as the distance between the insulating adhesive and the bottom plate, are reasonably set to meet the formula 0.001mm≤[(2D1+D2) / 2L]*H≤2.5mm. Within this range, the electrical safety between adjacent batteries is improved, avoiding safety risks such as short circuits between adjacent batteries. It also prevents adjacent batteries from expanding along the first direction, which would result in insufficient expansion space and lead to high internal pressure and the risk of thermal runaway, which could cause the battery to explode.

[0020] Research has found that the first walls of adjacent batteries are positioned relative to each other. The first walls of the batteries form the larger surface of the battery housing, allowing for significant internal expansion. The insulating adhesive placed between adjacent batteries reduces the expansion space within the battery cells during charging and discharging, leading to internal pressure buildup and the potential for abnormal opening of the battery's explosion-proof valve, compromising the overall safety of the battery pack. However, the absence of insulating adhesive between adjacent batteries results in a smaller electrical safety distance between them, creating a safety risk of overlapping connections.

[0021] If the formula [(2D1+D2) / 2L]*H is too narrow, the electrical insulation distance between adjacent batteries will be short, increasing the risk of battery short circuits. In addition to the first exposed area on the bottom of the metal casing, the side surfaces of the metal casing are also susceptible to short circuit risks due to insufficient electrical safety distance. If the formula is too wide, the excessive thickness and / or height of the insulating adhesive and insulation layer between batteries will lead to high internal pressure in the batteries, posing a safety risk of abnormal battery pressure release.

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0023] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0024] In addition, in the description of the present invention, the terms used are for illustrative purposes only and are not intended to limit the scope of the present invention. The terms "comprise" and / or "include" are used to specify the presence of the elements, steps, operations and / or components, but do not exclude the presence or addition of one or more other elements, steps, operations and / or components. The terms "first", "second" and the like may be used to describe various elements, do not represent an order, and do not limit these elements. In addition, in the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more. These terms are only used to distinguish one element from another. These and / or other aspects become apparent in conjunction with the following drawings, and it is easier for a person of ordinary skill in the art to understand the description of the embodiments of the present invention. The accompanying drawings are used to depict the embodiments of the present invention for illustrative purposes only. Those skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods shown in the present invention can be adopted without departing from the principles of the present invention.

[0025] For ease of understanding, the X-axis in the accompanying drawings represents the width of the battery pack, i.e., the width of the battery, or the first direction; the Y-axis represents the length of the battery pack, i.e., the length of the battery; and the Z-axis represents the height of the battery pack, i.e., the height of the battery. The positive direction of the Z-axis indicates the direction from the bottom surface of the battery pack to the top surface, i.e., the direction from the bottom surface of the battery pack to the top surface. References to "top" or "bottom" in any element of this disclosure can be made in this manner.

[0026] <Exemplary Battery Pack> An embodiment of the present invention provides a battery pack 100. The following first illustrates the overall structure of the battery pack 100 according to the present disclosure. It should be understood that the structure of the battery pack 100 is not limited to the following description. For example, one or more of the elements described below may be omitted or replaced, and their layout relationships may be altered.

[0027] See also Figures 1 to 6 The battery pack 100 includes a base plate 10 , a plurality of batteries 20 , an insulating adhesive 30 and a barrier 40 .

[0028] The battery 20 is a storage unit capable of repeated charge and discharge, and can be interpreted as a "secondary battery." In this application, the concept of "secondary battery" may include, but is not limited to, lithium-ion secondary batteries, sodium-ion secondary batteries, lead-acid batteries, and nickel-metal hydride batteries.

[0029] The battery 20 may be, for example, a prismatic battery, which can be understood as a quadrangular prism-shaped battery. The battery 20 may also be another type of battery that, when arranged along the first direction, has two opposing first walls 231 . The battery pack 100 of the present invention will be described in detail below using a prismatic battery as an example.

[0030] by Figure 1 For example, multiple batteries 20 in the battery pack 100 are arranged on the bottom plate 10 along a first direction. Figure 1 The area outlined by the dashed line can be understood as the smallest arrangement unit of multiple batteries 20, which can be called a battery pack or battery module. The battery pack 100 can include one battery module or multiple battery modules. The number of batteries 20 in each battery module can be determined based on the required capacity or voltage of the battery pack 100. This application does not specifically limit the number of batteries 20 contained in a battery module. The battery pack 100 described in this application will be specifically described below using a battery module as an example.

[0031] The first direction can be understood as the width direction of the battery pack 100, that is, multiple batteries 20 are arranged in sequence along the width direction of the battery pack 100 to form a battery module. One or more battery modules are assembled into corresponding boxes to form the battery pack 100.

[0032] It should be noted that the multiple batteries 20 may also be arranged along the length direction, height direction or other specific directions of the battery pack 100, and the first direction does not have a special meaning.

[0033] The bottom plate 10 can be understood as a part of the box body of the battery pack 100, that is, the bottom plate 10 is the bottom surface part of the box body. The bottom plate 10 can also be understood as an independent part, that is, it can be connected to the box body through a specific connection structure.

[0034] The base plate 10 serves to mount and support the batteries. It can be a simple support plate or a functional heat exchange plate. When used as a heat exchange plate, it has a central heat exchange channel that exchanges heat with the batteries via a heat exchange medium. Depending on the battery pack's operating environment and requirements, the heat exchange plate can provide both cooling and heating functions. The base plate 10 can be connected to the battery frame around its perimeter using fasteners, such as bolts, flow drill screws, or structural adhesive.

[0035] The bottom plate 10 is a metal plate, and the material of the metal plate can be aluminum, steel, copper, nickel, titanium or other metal materials or alloys thereof. Figure 6 Each battery 20 in the battery module includes a cell 22 and a metal housing 23. The metal housing 23 primarily provides protection and support for the battery 20, and the cell 22 is housed within the space formed by the metal housing 23. The metal housing 23 includes, for example, two opposing first walls 231, two opposing second walls 232, and a bottom surface 233. The area of ​​the first wall 231 is larger than that of the second wall 232.

[0036] Specifically, the two first walls 231 may be, for example, two walls disposed opposite each other in the width direction of the battery 20; the two second walls 232 may be, for example, two walls disposed opposite each other in the length direction of the battery 20; and the bottom surface 233 may be, for example, a surface located at the bottom end in the height direction of the battery 20. The two first walls 231, the two second walls 232, and the bottom surface 233 collectively form the accommodation space of the metal shell 23.

[0037] In this embodiment, multiple batteries 20 are arranged along the width direction of the battery pack 100, so that in the battery module composed of multiple batteries 20, the first walls 231 of any two adjacent batteries 20 are arranged relative to each other, that is, the walls with larger areas in the metal shell 23 are arranged relative to each other.

[0038] The first wall portion 231 is provided with an insulating layer 21. It will be appreciated that the insulating layer 21 is provided on the surface of the first wall portion 231 away from the battery cells 22. The surface of the first wall portion 231 away from the battery cells 22 can be referred to as the outer surface of the first wall portion 231. Providing an insulating layer on the outer surface of the first wall portion 231 can improve the insulation performance between two adjacent battery cells 20, thereby preventing insulation failure between any two adjacent battery cells 20 in the battery module due to contact between the opposing first walls 231.

[0039] Optionally, the insulating layer 21 may be an insulating film or an insulating coating, etc., which has an insulating function. The insulating film may be made of, for example, polyethylene terephthalate, polyimide, polypropylene, or acrylic adhesive. The insulating coating may be made of, for example, polyethylene terephthalate, polyimide, mica, UV coating material, or epoxy resin. Figures 3 to 5 The battery pack 100 further includes an insulating adhesive 30. The insulating adhesive 30 includes a first portion 31 and a second portion 32. The first portion 31 is disposed between two adjacent batteries 20 and securely connects the two adjacent batteries 20. The second portion 32 is disposed between the first exposed area of ​​the bottom surface 233 of the metal shell 23 and the bottom plate 10 and securely connects the batteries 20 and the bottom plate 10.

[0040] Specifically, the first portion 31 is disposed in the area between the two opposing first walls 231 of two adjacent batteries 20. That is, the first portion 31 is "sandwiched" between the first wall 231 on the right side of the first battery 20 and the first wall 231 on the left side of the second battery 20. It will be understood that the first portion 31 contacts the insulating layer 21 disposed on the outer surface of the first wall 231. Thus, the portion of the first wall 231 near the bottom surface 233 includes not only the insulating layer 21 but also the first portion 31. In this position, the insulating layer 21 and the first portion 31 can simultaneously insulate the batteries 20. In this manner, the first portion 31 not only improves the electrical safety of the two adjacent batteries 20 but also provides a certain adhesive and fixing effect on the two adjacent batteries 20, thereby enhancing the stability of the batteries 20 within the metal housing 23.

[0041] On this basis, the second portion 32 is disposed between the bottom surfaces 233 of two adjacent batteries and the bottom plate 10 . That is, the second portion 32 extends on the top surface of the bottom plate 10 along the width direction of the battery pack 100 .

[0042] Specifically, a first exposed area is provided on the bottom surface 233, and the second portion 32 is located between the first exposed area and the bottom plate 10. In this way, the battery 20 can be directly bonded to the bottom plate 10 via the second portion 32 of the first exposed area, thereby improving the stability of the bonding between the battery 20 and the bottom plate 10 and reducing the risk of separation between the two.

[0043] It should be noted that the first portion 31 and the second portion 32 can be formed in one step or in separate steps. For example, the second portion 32 can be formed on the base plate 10 first, and then the first portion 31 can be formed between two adjacent batteries 20. There is no clear dividing line between the first portion 31 and the second portion 32; the distinction is artificial. The first portion 31 and the second portion 32 do not have specific meanings.

[0044] Optionally, the insulating adhesive 30 may be, for example, polyurethane structural adhesive, acrylic structural adhesive, or epoxy structural adhesive, etc. The first portion 31 and the second portion 32 may be made of the same material or different materials, which is not specifically limited in this application.

[0045] Preferably, the elastic modulus of the first portion 31 is smaller than the elastic modulus of the second portion 32. In this way, the first portion 31 can provide expansion space for buffering two adjacent batteries 20, ensuring the orderly flow of gas inside the battery 20 and preventing the battery 20 from exploding prematurely due to excessive internal gas pressure.

[0046] The inventors have discovered that to achieve a stable connection between the battery 20 and the base plate 10 while also ensuring insulation between two adjacent battery cells 20 in the battery module, the dimensions of the insulating layer 21 and the insulating adhesive 30 can be set so that the dimensions satisfy the following relationship. This ensures both insulation between the battery 20 and the base plate 10 and insulation between two adjacent battery cells 20.

[0047] 0.001mm≤[(2D1+D2) / 2L] *H≤2.5mm (1) Wherein, D1 is the thickness of the insulating layer 21 in the first direction, in mm. That is, D1 is the thickness of the insulating film or insulating coating on the outer surface of the first wall portion 231 in the first direction. That is, at a certain position of the insulating layer 21, the vertical distance from the side close to the first wall portion 231 to the side away from the first wall portion 231. It can be understood that the thickness of the insulating layer 21 should be understood as a uniform thickness, that is, the thickness at all positions of the insulating layer 21 is equal. For the case where the thickness of some positions of the insulating layer 21 is different from that of other positions, the average value of the overall thickness of the insulating layer 21 can be used as the value of D1. The larger the value of D1, the better the insulation effect of the insulating layer 21 will be. Conversely, the smaller the value of D1, the worse the insulation effect of the insulating layer 21 will be.

[0048] D2 is the thickness of the first part 31 in the first direction, in mm. For example, D2 can be understood as the vertical distance from the outer surface of the insulating layer 21 on the right side of the first battery 20 to the outer surface of the insulating layer 21 on the left side of the second battery 20, among two adjacent batteries 20. It can be understood that the thickness of the first part 31 is a uniform thickness, that is, the thickness at all positions of the first part 31 is equal. In the case where the thickness of the first part 31 is uneven, the average value of the overall thickness of the first part 31 can be used as the value of D2. The larger the value of D2, the better the insulation effect between the two adjacent batteries 20; conversely, the smaller the value of D2, the worse the insulation effect between the two adjacent batteries 20.

[0049] L is the length of the battery 20 in the first direction, measured in mm. For example, L can be understood as the distance between two opposing first walls 231 of the battery 20, i.e., the distance between the outer surface of one first wall 231 and the outer surface of the other first wall 231. It is understood that L should be understood as the distance between the two first walls 231 when the metal shell 23 is not deformed. The value of L will vary depending on the battery 20. This application primarily focuses on the proportional relationship between L and several other elements.

[0050] H is the distance between the top of the first part 31 and the top surface of the bottom plate 10, in mm. For example, H can be understood as the vertical distance between the end of the first part 31 away from the bottom plate 10 and the top surface of the bottom plate 10 at its corresponding position. It can be understood that the distances between each position of the top of the first part 31 and the top surface of the bottom plate 10 are equal. If the distances between each position of the top of the first part 31 and the top surface of the bottom plate 10 are not equal, the average value of the distances between each position of the first part 31 and the top surface of the bottom plate 10 can be used as the value of H. The larger the value of H, the better the insulation effect between two adjacent batteries 20; conversely, the smaller the value of H, the worse the insulation effect between two adjacent batteries 20.

[0051] For ease of description, the above inequality is hereinafter referred to as Equation 1. The battery pack 100 that satisfies the above range can not only ensure a firm bond between the battery 20 and the bottom plate 10 , but also ensure insulation between two adjacent batteries 20 .

[0052] It can be understood that, on the basis that Formula 1 satisfies the above range, the thickness D1 of the insulating layer 21 in the first direction satisfies a certain value range, for example, D1 satisfies: 0.05 mm≤D1≤0.2 mm.

[0053] Optionally, D1 can be 0.06mm, 0.08mm, 0.1mm, 0.12mm, 0.15mm, 0.16mm, 0.18mm, 0.19mm, etc. D1 that meets the above range can not only ensure that the insulating layer 21 has sufficient thickness to provide a good insulation effect for the battery 20, but also is not easily scratched during use, further improving the insulation performance of the battery 20; at the same time, the thickness of the insulating layer 21 will not be too large, that is, it will not have a substantial impact on the energy density of the battery 20, and the energy density of the battery 20 can still be kept within a relatively ideal range.

[0054] Similarly, on the basis that Formula 1 satisfies the above range, the first portion 31 of the insulating adhesive 30 satisfies a certain value range. For example, the first portion 31 satisfies: 0.2 mm ≤ D2 ≤ 0.7 mm, and / or 0.5 mm ≤ H ≤ 20 mm.

[0055] Optionally, D2 may be 0.3 mm, 0.4 mm, 0.5 mm, or 0.6 mm, etc. H may be 2 mm, 5 mm, 6 mm, 8 mm, 10 mm, 12 mm, 15 mm, 16 mm, 17 mm, 18 mm, or 19 mm, etc.

[0056] D2 that meets the above range can, on the one hand, ensure that there is a sufficient safety distance between two adjacent batteries 20, that is, it can ensure that there is no risk of short circuit between the two batteries 20; at the same time, it will not make the gap between two adjacent batteries 20 too large, affecting the energy density of the battery pack 100.

[0057] When H satisfies the above range, on the one hand, the first portion 31 can be extended a sufficient distance in the height direction of the battery 20, thereby improving the risk of insulation failure caused by the direct bonding of the bottom surface 233 of the metal shell 23 to the base plate 10; at the same time, the height of the first portion 31 will not be too large, that is, sufficient expansion space can be reserved for two adjacent batteries 20, thereby reducing the risk of thermal runaway of the battery 20 due to excessive internal pressure.

[0058] In addition, battery 20 satisfies 25 mm ≤ L ≤ 150 mm. For example, L can be 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, 120 mm, 130 mm, or 140 mm. During use, L can be determined based on the requirements of battery 20, and D1, D2, and H can be determined based on the value of L.

[0059] It is understood that only a portion of the bottom surface 233 can be set as the first exposed area, or the entire bottom surface 233 can be set as the first exposed area. When the entire bottom surface 233 is set as the first exposed area, the risk of short circuit between adjacent batteries 20 increases, and the range of formula 1 needs to be appropriately adjusted to improve the insulation effect between adjacent batteries 20. For example, the insulating layer 21 and the insulating glue 30 satisfy the following relationship: 0.04mm≤[(2D1+D2) / 2L] *H≤2.5mm (2) Meeting the above range can not only ensure a strong bond between the battery 20 and the bottom plate 10 , but also ensure an insulation effect between two adjacent batteries 20 .

[0060] In an optional embodiment, the insulating layer 21 completely covers the first wall portion 231. In other words, the orthographic projection of the insulating layer 21 on the first wall portion 231 completely overlaps with the first wall portion 231. For example, it can be understood that the length of the insulating layer 21 in the longitudinal direction of the battery 20 is equal to the length of the first wall portion 231 in the longitudinal direction of the battery 20; and the height of the insulating layer 21 in the height direction of the battery 20 is equal to the height of the first wall portion 231 in the height direction of the battery 20.

[0061] Specifically, taking a square battery as an example, the upper edge of the insulating layer 21 is flush with the upper edge of the first wall portion 231; the lower edge of the insulating layer 21 is flush with the lower edge of the first wall portion 231; the left edge of the insulating layer 21 is flush with the left edge of the first wall portion 231; and the right edge of the insulating layer 21 is flush with the right edge of the first wall portion 231.

[0062] At this time, the insulation effect between two adjacent batteries 20 is better and the risk of failure is reduced, so the range of formula 1 can be appropriately adjusted. The relevant dimensions of the insulating layer 21 and the insulating glue 30 can satisfy the following relationship: 0.001mm≤[(2D1+D2) / 2L] *H≤2.5mm (3) Meeting this range not only ensures effective insulation between the battery 20 and the base plate 10, but also minimizes the size of the insulating adhesive between two adjacent batteries 20. This leaves more space between two adjacent batteries 20, preventing the explosion-proof valve of the battery 20 from abnormally opening due to insufficient expansion space after the battery 20 expands.

[0063] In an optional embodiment, the insulating layer 21 extends onto the bottom surface 233. That is, the insulating layer 21 not only completely covers the first wall portion 231 but also partially extends onto the bottom surface 233. In this way, a portion of the bottom surface 233 is also covered by the insulating layer 21, increasing the creepage distance between two adjacent batteries 20 and reducing the risk of short circuits between the two adjacent batteries 20.

[0064] Preferably, the ratio of the dimensions C and L of the insulating layer 21 extending on the bottom surface 233 is 0.02 ≤ C / L ≤ 0.3. Meeting this range ensures that the insulating layer 21 extends sufficiently large to reduce the risk of short circuits between adjacent batteries 20. Furthermore, it ensures that the insulating layer 21 extends sufficiently large to avoid affecting the bonding strength between the batteries 20 and the base plate 10.

[0065] The value range of C is 1 mm to 10 mm. For example, C can be 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, or 9 mm.

[0066] In an optional embodiment, the insulating layer 21 partially covers the first wall portion 231 , thereby providing a second exposed area on the first wall portion 231 , and the first portion 31 at least partially covers the second exposed area.

[0067] It will be appreciated that when the insulating layer 21 does not completely cover the first wall portion 231, that is, a second exposed area exists on the first wall portion 231, and the portion of the metal housing 23 corresponding to the second exposed area is exposed. Partially or completely covering the second exposed area with the first portion 31 can insulate the metal housing 23 within the second exposed area, reducing the risk of short circuits between adjacent batteries 20. Furthermore, the first portion located in the second exposed area can also act as a bond between adjacent batteries 20, thereby improving the overall strength between the two adjacent batteries 20.

[0068] At this point, the height H of the first portion 31 can be adjusted appropriately. For example, the value range of H is 5 mm to 20 mm. Within this range, H ensures that the first portion 31 is high enough to reduce the risk of short circuits between adjacent batteries 20. Furthermore, H is not excessively large, thereby leaving more space between adjacent batteries 20, preventing the batteries 20 from having too little room to expand and reducing the risk of thermal runaway between adjacent batteries 20.

[0069] It is easy to understand that when the first wall portions 231 of two adjacent batteries 20 are both provided with second exposed areas, the risk of short circuit between the two adjacent batteries 20 will increase. In this case, the range of formula 1 can be appropriately adjusted to reduce the risk of short circuit between the two batteries 20. For example, the range of formula 1 can be adjusted to: 0.05mm≤[(2D1+D2) / 2L] *H≤2.5mm (4) When the range of Formula 4 is satisfied, the thickness of the insulating layer 21 and / or the first portion 31 in the first direction can be increased, and / or the height H of the first portion 31 can be increased. This increases the creepage distance between two adjacent batteries 20 and reduces the risk of short circuits between the two adjacent batteries 20.

[0070] In an optional embodiment, as Figure 7 As shown, in a direction perpendicular to the bottom plate 10 , a first gap 50 is formed between the edge of the insulating layer 21 on the first wall portion 231 that is parallel to and close to the bottom surface 233 and the bottom surface 233 . In other words, the insulating layer 21 does not completely cover the first wall portion 231 .

[0071] Specifically, let's take a square battery as an example: the lower edge of the insulating layer 21 is not flush with the lower edge of the first wall portion 231, so that a first gap 50 will exist between the lower edge of the insulating layer 21 and the lower edge of the first wall portion 231. It can be understood that the first wall portion 231 located in the area of ​​the first gap 50 is exposed to the outside, that is, there is a risk of insulation failure in this part of the first wall portion 231. In view of this, the range of Formula 1 can be appropriately adjusted so that the insulating layer 21 and the insulating glue 30 that satisfy the following relationship can still ensure the insulation effect of the battery pack 100. At this time, the insulating layer 21 and the insulating glue 30 satisfy: 0.01mm≤[(2D1+D2) / 2L]H≤2.5mm (5) For ease of description, the above relationship is referred to as Formula 5 below. When Formula 5 satisfies the above range, it can ensure stable adhesion between the battery 20 and the base plate 10; at the same time, it can also ensure the insulation effect between two adjacent batteries 20.

[0072] Furthermore, in a direction perpendicular to the base plate 10, H is greater than the height of the first spacer 50. This means that the first portion 31 extends farther in the height direction of the battery 20 than the first spacer 50 does. This allows the first portion 31 to insulate the first wall 231 within the first spacer 50, reducing the risk of insulation failure between adjacent batteries 20 due to the first spacer 50.

[0073] Preferably, the height of the first spacer 50 in a direction perpendicular to the bottom plate 10 ranges from 0.1 mm to 0.3 mm. A first spacer 50 within this range ensures a sufficiently large insulating layer 21 on the first wall 231 to reduce the risk of short circuits between adjacent batteries 20.

[0074] In an optional embodiment, the dielectric constant of the insulating adhesive 30 ranges from 2 F / m to 5.5 F / m. For example, the dielectric constant of the insulating adhesive 30 may be 2.5 F / m, 3.0 F / m, 3.5 F / m, 4.0 F / m, or 4.5 F / m. Insulating adhesive 30 within the above range can ensure its insulation effect and improve the safety performance between adjacent batteries 20.

[0075] See also Figure 4 In an optional embodiment, the battery pack 100 further includes a barrier 40 located between the first wall portions 231 of any two adjacent batteries 20. The barrier 40 may be, for example, a partition or a barrier frame, or other structural member with a certain degree of structural strength. This barrier 40 can provide a certain degree of isolation between adjacent batteries 20, increasing the creepage distance between adjacent batteries 20 and further reducing the risk of insulation failure between adjacent batteries 20.

[0076] Alternatively, the barrier 40 may be, for example, a heat exchange plate or thermal pad with heat exchange function to prevent heat conduction between adjacent batteries 20. In this case, the barrier 40 may be made of a heat-insulating aerogel or silicone frame, or a metal heat exchange plate with a heat exchange channel disposed therein containing a liquid, gas, or a phase-changing cooling medium.

[0077] It is understood that the thickness of the barrier 40 should be less than that of the first portion 31. In other words, the barrier 40 does not contact the first wall portions 231 of two adjacent batteries 20. This allows sufficient expansion space for the two adjacent batteries 20, reducing the risk of thermal failure of the batteries 20 due to excessive internal pressure.

[0078] Furthermore, a portion of the barrier 40 is fixedly connected to the insulating adhesive 30. It will be appreciated that the portion of the barrier 40 adjacent to the insulating adhesive 30 is fixedly connected to the insulating adhesive 30. That is, the bottom of the barrier 40 is bonded to the first portion 31. For example, the bottom of the barrier 40 is inserted into the first portion 31. In this way, the first portion 31 can secure the barrier 40, eliminating the need for an additional fixing structure for the barrier 40, which helps reduce the weight of the battery 20. Furthermore, the fixed connection between the barrier 40 and the first portion 31 eliminates any potential short circuits between the first wall portions 231 of adjacent batteries 20, further improving the insulation between the two adjacent batteries 20.

[0079] Alternatively, see Figure 5 A second gap 60 exists between the barrier 40 and the insulating adhesive 30. This means that the bottom of the barrier 40 does not contact the first portion 31, and a second gap 60 exists between them along the height of the battery 20. This second gap 60 also allows for expansion of the battery 20, reducing the risk of thermal runaway.

[0080] It is understood that, at this time, the barrier 40 can be fixed by its upper portion. For example, the barrier 40 can be fixed by its upper portion to the top surface of the metal shell 23. The barrier 40 can also be fixed by other means, which are not specifically limited in this application.

[0081] In an optional embodiment, in a direction perpendicular to the bottom plate 10 , the height of the battery cell 22 is M, and the ratio of H to M is in the range of 0.002-0.15.

[0082] The height of the battery cell 22 herein can be understood as the height excluding the terminal column. When the first portion 31 falls within the above range, the first portion 31 has a sufficient height to reduce the risk of short circuits between adjacent batteries 20. At the same time, the height of the first portion 31 is not excessively large, thereby preventing the risk of the battery cell 22 falling off and the battery 20's explosion-proof valve abnormally opening due to limited expansion space.

[0083] In an optional embodiment, the battery 20 further includes an explosion-proof valve, which is provided on the bottom surface 233 of the metal shell 23. It is understandable that the explosion-proof valve is generally subjected to thinning or defect treatment to facilitate the release of pressure in the metal shell 23. At this time, the insulating glue 30 at the corresponding position of the explosion-proof valve is set to a hollow structure to expose the explosion-proof valve. That is to say, no insulating glue is provided at the position corresponding to the explosion-proof valve. As a result, the bonding area of ​​the insulating glue 30 between the battery 20 and the base plate 10 will be reduced, and the range of Formula 1 can be further limited so that the insulating layer 21 and the insulating glue 30 that satisfy the following relationship can not only achieve stable bonding between the battery 20 and the base plate 10, but also ensure the insulation effect of the battery pack 100. At this time, the insulating layer 21 and the insulating glue 30 satisfy: 0.15mm≤[(2D1+D2) / 2L]H≤2.5mm (6).

[0084] For ease of description, the above relationship is referred to as Formula 6 below. When Formula 6 satisfies the above range, it can ensure stable adhesion between the battery 20 and the base plate 10; at the same time, it can also ensure the insulation effect between two adjacent batteries 20.

[0085] In an optional embodiment, the battery cell 22 includes a bottom support plate, which is located between the bottom surface of the battery cell 22 and the metal shell 23 .

[0086] The optional end of the first portion 31 away from the bottom plate 10 is located above the bottom support plate. In other words, the top of the first portion 31 is located higher than the top of the bottom support plate in the height direction of the battery 20. Furthermore, the extension distance of the first portion 31 in the height direction of the battery 20 should be less than 2 / 5 of the height of the battery 20.

[0087] At this time, the space for the battery cell 22 to expand during the charge and discharge process is reduced. In order to ensure the thermal stability of the battery 20, the range of formula 1 needs to be appropriately adjusted. That is, the insulating layer 21 and the insulating glue 30 satisfy the following relationship: 0.001mm≤[(2D1+D2) / 2L]*H≤2.0mm (7) For ease of description, the above relationship will be referred to as Formula 7 below. When Formula 7 satisfies the above range, it can not only ensure the insulation effect between two adjacent batteries 20, but also ensure that there is enough expansion space for the two adjacent batteries 20, thereby avoiding the problem of abnormal explosion of the explosion-proof valve due to the small expansion space.

[0088] Alternatively, the end of the first portion 31 near the bottom plate 10 is located below the bottom support plate. That is, the bottom end of the first portion 31 is located lower than the bottom end of the bottom support plate in the height direction of the battery 20. This prevents the battery cell 22 from being squeezed by the insulating adhesive 30 after expansion, which could cause the battery cell 22 to fall off, and provides more space for the battery cell 22 to expand.

[0089] In an optional embodiment, the battery 20 further includes a pole 24, which is located on the surface of the metal shell 23 facing the bottom plate 10. The pole 24 can be understood as a current output terminal of the battery 20, for example, to achieve series or parallel connection between adjacent batteries 20.

[0090] It is understandable that when the terminal 24 is located on the surface of the metal shell 23 facing the bottom plate 10, the bonding area between the battery 20 and the bottom plate 10 will be reduced, and the range of formula 1 can be appropriately adjusted. The inventors found that when formula 1 satisfies the following relationship, it can not only ensure the bonding strength between the battery 20 and the bottom plate 10, but also ensure the insulation effect between adjacent batteries 20. At this time, the insulating layer 21 and the insulating glue 30 meet: 0.015mm≤[(2D1+D2) / 2L]*H≤2.5mm (8) For ease of description, the above relationship is referred to as Formula 8 below. When Formula 8 satisfies the above range, it can ensure stable adhesion between the battery 20 and the base plate 10; at the same time, it can also ensure the insulation effect between two adjacent batteries 20.

[0091] Alternatively, the pole 24 is located on the surface of the metal shell 23 facing away from the base plate 10. That is, the pole 24 is located on the top surface of the metal shell 23. In this case, the pole 24 is farther away from the first exposed area of ​​the bottom surface 233, avoiding the risk of a short circuit between the pole 24 and the first exposed area. In this way, the range of Equation 1 can be appropriately adjusted to reserve more expansion space between adjacent batteries 20 while ensuring the insulation effect. In this case, the insulating layer 21 and the insulating glue 30 can meet the following requirements: 0.001mm≤[(2D1+D2) / 2L]*H≤2.2mm (9).

[0092] For ease of description, the above relationship will be referred to as Formula 9 below. When Formula 9 satisfies the above range, it can ensure the electrical safety of the battery 20; at the same time, it can also ensure that there is sufficient expansion space between two adjacent batteries 20 to avoid the abnormal explosion of the explosion-proof valve due to too small expansion space.

[0093] <Exemplary Electric Equipment> An embodiment of the present invention further provides an electric device, which may include the battery pack 100 described above.

[0094] By way of example only, the electrical equipment may be, but is not limited to, a vehicle, a ship, an aircraft, a household appliance, an industrial equipment, etc. For example, the vehicle may be a car, a truck, an engineering vehicle, etc.

[0095] The following will describe in detail the effects of the insulating layer 21 and the insulating adhesive 30 on the insulation performance and thermal runaway of the battery 20 through specific embodiments.

[0096] Battery preparation method: The battery can be a lithium-ion battery, a sodium-ion battery, a sodium-lithium-ion battery, a lithium metal battery, a sodium metal battery, a lithium-sulfur battery, a magnesium-ion battery, a nickel-metal hydride battery, a nickel-cadmium battery, a lead-acid battery, etc., which is not limited in this embodiment. The battery can generally include a battery shell, a battery cell, a switching plate and an electrolyte, and the battery shell is used to accommodate the battery cell and the electrolyte. The battery shell generally includes a battery shell body and a cover plate, and at least one positive electrode post and at least one negative electrode post are arranged on the shell and / or the cover plate. The battery cell includes one or more electrode assemblies, and the electrode assembly is formed by stacking or winding a positive electrode sheet, a negative electrode sheet and a diaphragm. The diaphragm is located between adjacent positive and negative electrodes to insulate the positive and negative electrodes, and a tab is extended from at least one end of the electrode assembly. One end of the switching plate is electrically connected to the tab, and the other end is electrically connected to the electrode post.

[0097] Taking the wound battery cell as an example, the specific preparation process is as follows: the positive electrode sheet, the negative electrode sheet and the separator are wound to form an electrode assembly. The tab is extended from one end of the electrode assembly. When the tab is fixed to the adapter, the electrode assembly and the tab are first placed along the tab extension direction; then the tab of the electrode assembly is welded to the tab welding area of ​​the adapter; then the adapter is welded to the pole post on the cover plate at the pole post welding area of ​​the adapter. After welding, the pole post and the tab are located on the same side in the thickness direction of the adapter, and then the electrode assembly is folded along the connection position between the tab and the electrode assembly. The electrode assembly and the pole post are located on both sides in the thickness direction of the adapter, and the folded electrode assembly is placed into the shell, and the cover plate and the battery shell body are welded and sealed. Liquid is injected, formed, and the liquid injection hole is sealed to obtain a single battery.

[0098] Test method: Multiple groups of batteries were prepared according to conventional preparation methods, with 45 batteries in each group. The batteries in each group had the same performance and structural parameters except for the battery size L. An insulating layer was applied to each of the four sides of the battery, such as an insulating film made of a specific material. The insulating film had the same performance and structural parameters and the same covering area except for the thickness D1. Sample batteries were obtained, and in order to facilitate the recording of the battery valve opening pressure during the battery thermal runaway test, pressure sensors were installed inside the batteries during the battery preparation process.

[0099] A batch of battery boxes with the same structure, size and material were selected. The 45 sample batteries in each group were arranged and packed in rows of 15 along the width of the battery. Three rows were installed in each battery box and bonded to the battery base plate with polyurethane structural adhesive. The thickness of the adhesive layer on the bottom of the battery is 1.5mm. The thickness D2 and height H of the first part of the insulating adhesive between adjacent batteries in each battery pack are different. The assembled battery pack was placed in a 45°C environment and left to stand for 48 hours to obtain a sample battery pack. The specific parameters of L, D1, D2 and H mentioned above are detailed in Table 1.

[0100] 1. Insulation test: The batteries in the sample battery packs were subjected to insulation voltage tests. The positive and negative terminals of the insulation voltage tester were connected to the exposed portion of the covers of two adjacent sample batteries, i.e., where the QR code on the battery cover protrudes from the casing. The voltage meter was set to 4000V DC for 60 seconds, and the maximum leakage current during the test was measured in mA. Ten groups were randomly measured within each sample battery pack; any group with a leakage current exceeding 0.5mA was deemed unqualified.

[0101] 2. Thermal runaway test: Thermal runaway testing was performed on five areas within each sample battery pack. Specifically, the four corners and the center of the battery pack were selected. The pressure at which the battery explosion-proof valves burst in each of these areas was recorded. The maximum pressure minus the minimum pressure was subtracted. A test failure was considered unqualified if the difference between the two exceeded 0.4 MPa. This indicates abnormal battery pressure release within the battery pack, resulting in a significant deviation in the battery pack's burst pressure, impacting battery pack performance.

[0102] Specific test method: fully charge the battery pack to 100% SOC, let it stand for 24 hours, ensure that the voltage and temperature are stable, and the ambient temperature is 25°C.

[0103] Table 1 Specific parameters and test results of each embodiment Install the heating device in the center of the first wall (large surface) of the target battery, tightly attaching the high-temperature heating plate. The high-temperature heating plate has a power of 150W and a temperature resistance of 500°C. Use high-temperature tape to fix the high-temperature heating plate to the first wall, ensuring that there is no gap between the two. Connect the power cord of the heating plate to an external programmable power supply and heat the target battery at a constant power of 150W. If the battery temperature is ≥150°C and the temperature rise rate is greater than 1°C / s, or the voltage drops by more than 20%, the battery is judged to be in thermal runaway, and the internal pressure sensor of the battery records the burst pressure.

[0104] Following the above scheme, a new battery pack of the same specifications was used, with identical heater plate location / power, and sensor layout. The test was then repeated in another of the five battery pack zones. Thermal runaway valve opening pressure tests were performed on all five zones within the same battery pack, analyzing the differences in thermal runaway characteristics and explosion-proof valve opening pressures in different zones.

[0105] According to the test results in Table 1, it can be seen that in Examples 1 to 17, the performance parameters of the sample batteries selected for testing meet the following requirements: 0.001≤((2D1+D2) / 2L)*H≤2.5. In the insulation test, the test requirements were met. That is, the leakage current between the two adjacent sample batteries tested was less than 0.5mA, which met the insulation performance requirements. In the thermal runaway test, when the batteries in the five areas of the sample battery pack thermally ran away, the difference in burst pressure between the two adjacent sample batteries tested was less than 0.4Mpa. This proves that the working environment of the batteries inside the battery pack is normal, the pressure of the battery explosion-proof valve is normal, and the design requirements are met.

[0106] In Examples 13 to 17, the performance parameters of the sample batteries tested met the following conditions: 0.001 ≤ ((2D1 + D2) / 2L) * H ≤ 2.5, which met the test requirements for the insulation test and thermal runaway test. However, the selection of battery parameters such as D1, D2, H, and L was found to have a certain impact on battery performance. Among them: In Examples 14 and 17, D1 is relatively small, which may result in the insulation layer being punctured during battery assembly. Furthermore, the battery may expand and squeeze the insulation film during use, posing a risk of insulation film failure.

[0107] In Examples 15 to 17, D2 is larger. During testing, it was found that when multiple batteries were placed in the box, the size increased, requiring greater preload force to clamp the batteries. Furthermore, the distance between adjacent batteries was larger, reducing the number of batteries that could be accommodated in the same battery pack and the pack's energy density. Heat dissipation during battery use was also affected.

[0108] In Example 13, D2 is relatively small, and the first portion of the insulating glue between two adjacent batteries is easily squeezed and thinned when the batteries are assembled into a box, which poses a certain risk of insulation failure.

[0109] In Example 13 and Example 16, L is relatively small, and a larger number of batteries can be assembled in the same battery box. The battery shell occupies a larger space, resulting in a larger weight of the battery pack.

[0110] In Example 15, L is relatively large, and the battery width is relatively large, which makes it difficult to assemble the battery into a box during the preparation process.

[0111] In Examples 13 and 16, H is small, and the risk of insulation failure between two adjacent batteries increases.

[0112] In Examples 14 and 17, H is relatively large, which increases the constraint area when the battery expands, affecting the charge and discharge performance of the battery.

[0113] In Comparative Examples 1 to 3, the performance parameters of the sample batteries tested met the following range: ((2D1+D2) / 2L)*H<0.001. In the thermal runaway test, when the batteries in the five regions of the sample battery pack experienced thermal runaway, the difference in burst pressure between any two batteries was less than 0.4 MPa, proving that the battery operating environment within the battery pack was normal and the battery burst valve pressure was normal, meeting the design requirements. However, in the insulation test, the leakage current between adjacent batteries was greater than 0.5 mA, indicating that the insulation performance of the test sample batteries did not meet the design requirements.

[0114] In Comparative Examples 4 to 6, the performance parameters of the sample batteries selected for testing meet the following range: ((2D1+D2) / 2L)*H>2.5. In the insulation test, the test requirements were met, and the leakage current between any two adjacent sample batteries tested was less than 0.5mA, meeting the insulation performance requirements. However, in the thermal runaway test, when the batteries in the five areas of the sample battery pack thermally ran away, the difference in bursting pressure between any two adjacent batteries was greater than 0.4Mpa. This shows that there is an abnormality in the battery bursting pressure in the sample battery pack, and some sample batteries affect the valve opening pressure during operation, which does not meet the thermal runaway design requirements.

[0115] In the description provided herein, numerous specific details are described. However, it is understood that embodiments of the present invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques are not shown in detail so as not to obscure the understanding of this description.

[0116] Furthermore, persons of ordinary skill in the art will appreciate that although some embodiments described herein include certain features and not other features included in other embodiments, the combination of features from different embodiments is intended to be within the scope of the invention and to form different embodiments.

[0117] It will be appreciated by those skilled in the art that although the present invention has been described with reference to exemplary embodiments, various changes may be made and equivalents may be substituted for its elements without departing from the scope of the present invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present invention without departing from the essential scope of the present invention.

Claims

1. A battery pack, characterized in that: include: base plate; A plurality of batteries are arranged and fixedly disposed on the base plate along a first direction, each battery comprising a metal shell, the metal shell comprising two first walls disposed opposite each other, and two second walls disposed opposite each other, the area of ​​the first wall being greater than the area of ​​the second wall; the first walls of two adjacent batteries in the plurality of batteries are disposed opposite each other, an insulating layer being provided on an outer surface of the first wall, and the first direction being perpendicular to the first wall; The metal shell further includes a bottom surface, the bottom surface is arranged toward the bottom plate, and the bottom surface is provided with a first exposed area; an insulating adhesive comprising a first portion and a second portion, wherein the first portion is disposed between two adjacent batteries and fixedly connects the two adjacent batteries, and at least a portion of the second portion is disposed between the first exposed area and the bottom plate and fixedly connects the batteries and the bottom plate; The insulating layer and the insulating adhesive meet the following requirements: 0.001mm≤[(2D1+D2) / 2L]*H≤2.5mm Wherein, D1 is the thickness of the insulating layer in the first direction, in mm; D2 is the thickness of the first part in the first direction, in mm; L is the length of the battery in the first direction, in mm; H is the distance between the top of the first part and the top surface of the base plate, in mm.

2. The battery pack according to claim 1, wherein: The insulating layer completely covers the first wall portion, and the insulating layer and the insulating glue meet the following requirements: 0.001mm≤[(2D1+D2) / 2L] *H≤2.1mm.

3. The battery pack according to claim 2, wherein: The insulating layer extends to the bottom surface.

4. The battery pack according to claim 3, wherein: In the first direction, a ratio of an extension dimension C of the insulating layer on the bottom surface to the extension dimension L is 0.02≤C / L≤0.

3.

5. The battery pack according to claim 4, wherein: In the first direction, an extension dimension C of the insulating layer on the bottom surface ranges from 1 mm to 10 mm.

6. The battery pack according to claim 1, wherein: The insulating layer partially covers the first wall portion, so that the first wall portion has a second exposed area; the first portion at least partially covers the second exposed area.

7. The battery pack according to claim 6, wherein: The value range of H is 5mm-20mm.

8. The battery pack according to claim 6, wherein: The first portion completely covers the second exposed area.

9. The battery pack according to claim 6, wherein: The first wall portions of two adjacent batteries arranged opposite to each other are both provided with the second exposed area, and the insulating layer and the insulating glue meet the following requirements: 0.05mm≤[(2D1+D2) / 2L]*H≤2.5mm.

10. The battery pack according to claim 1, wherein: The elastic modulus of the first portion is smaller than the elastic modulus of the second portion.

11. The battery pack according to claim 1, wherein: In a direction perpendicular to the bottom plate, a first gap is formed between an edge of the insulating layer provided on the first wall portion that is parallel to and close to the bottom surface and the bottom surface, and the insulating layer and the insulating glue satisfy: 0.01mm≤[(2D1+D2) / 2L]*H≤2.5mm.

12. The battery pack according to claim 3, wherein: In a direction perpendicular to the bottom plate, the height H is greater than a height of the first interval.

13. The battery pack according to claim 11, wherein: In a direction perpendicular to the bottom plate, the height of the first interval ranges from 0.1 mm to 0.3 mm.

14. The battery pack according to claim 1, wherein: The dielectric constant of the insulating glue ranges from 2F / m to 5.5F / m.

15. The battery pack according to claim 1, wherein: Also included is a barrier located between the first wall portions of two adjacent batteries; Part of the barrier is fixedly connected to the insulating adhesive.

16. The battery pack according to claim 1, wherein: Also included is a barrier located between the first wall portions of two adjacent batteries; The barrier element is not in contact with the insulating adhesive.

17. The battery pack according to any one of claims 1 to 16, wherein: The battery further includes a cell, which is disposed inside the metal shell. In a direction perpendicular to the bottom plate, the height of the cell is M, in mm, and the ratio H / M is in the range of 0.002-0.

15.

18. The battery pack according to any one of claims 1 to 16, wherein: The battery further includes an explosion-proof valve, which is provided on the bottom surface. The insulating layer and the insulating adhesive meet the following requirements: 0.15mm≤[(2D1+D2) / 2L]*H≤2.5mm.

19. The battery pack according to claim 18, wherein: The position where the insulating glue is opposite to the explosion-proof valve is set as a hollow structure to expose the explosion-proof valve.

20. The battery pack according to claim 17, wherein: The battery cell includes a bottom supporting plate, and the bottom supporting plate is located between the bottom surface of the battery cell and the metal shell.

21. The battery pack according to claim 20, wherein: One end of the first portion away from the bottom plate is located above the bottom support plate, and the insulating layer and the insulating adhesive meet the following requirements: 0.001mm≤[(2D1+D2) / 2L]*H≤2.0mm.

22. The battery pack according to claim 20, wherein: One end of the first portion close to the bottom plate is located below the bottom supporting plate.

23. The battery pack according to claim 1, wherein: The battery further includes a pole, which is located on a surface of the metal shell facing the bottom plate, and the insulating layer and the insulating glue meet the following requirements: 0.015mm≤[(2D1+D2) / 2L]*H≤2.5mm.

24. The battery pack according to claim 1, wherein: The battery further includes a pole, which is located on a surface of the metal shell facing away from the bottom plate, and the insulating layer and the insulating glue meet the following requirements: 0.001mm≤[(2D1+D2) / 2L]*H≤2.2mm.

25. The battery pack according to claim 1, wherein: The entire bottom surface is configured as the first exposed area, and the insulating layer and the insulating adhesive meet the following requirements: 0.04mm≤[(2D1+D2) / 2L]*H≤2.5mm.

26. The battery pack according to claim 1, wherein: The insulating layer satisfies: 0.05mm≤D1≤0.2mm.

27. The battery pack according to claim 1, wherein: The insulating adhesive meets the following requirements: 0.2mm≤D2≤0.7mm, and / or 0.5mm≤H≤20mm.

28. The battery pack according to claim 1, wherein: The battery meets the following requirements: 25mm≤L≤150mm.

29. The battery pack according to claim 1, wherein: The plurality of batteries are square batteries.

30. An electrical device, characterized in that: Comprising a battery pack as described in any one of claims 1 to 16.

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