Battery pack, energy storage apparatus and energy storage system

Abstract

The embodiments of the present application relate to the technical field of batteries. Disclosed are a battery pack, an energy storage apparatus and an energy storage system. A conductive structural adhesive is provided between an insulating layer of each battery and the bottom of a first case. When the battery pack is at a high electric field strength, even if there are bubbles inside the structural adhesive, due to the conductivity of the structural adhesive, charges in the structural adhesive move under the high electric field strength, such that the voltages at various positions in the structural adhesive reach a balance, and a high voltage difference is not to be formed at the bubbles of the structural adhesive. Therefore, partial discharge is not to be generated in the bubbles of the structural adhesive, preventing the insulating layer on the outer surface of the battery from losing an insulating effect due to aging under the long-term effect of the partial discharge, thereby avoiding thermal runaway caused by a short circuit between the battery and the first case of the battery pack, and also ensuring that the battery pack can pass partial-discharge testing and thus be put into use.

Description

Battery packs, energy storage devices and energy storage systems

[0001] Related applications

[0002] This application claims priority to Chinese patent application No. 202520098499.8, filed on January 16, 2025, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of battery technology, specifically to a battery pack, energy storage device, and energy storage system. Background Technology

[0004] The battery pack consists of multiple batteries connected in series, parallel, or in a series-parallel configuration. Each battery is fixed to the bottom of the battery pack casing with structural adhesive, which serves the dual purpose of fixing the battery and insulating it from the ground.

[0005] Due to the characteristics and process limitations of structural adhesives, it is difficult to completely eliminate the presence of air bubbles inside after the structural adhesive has cured. When the battery pack is under a high electric field strength, the air bubbles inside the structural adhesive may become the starting point of partial discharge. The structural adhesive and even the insulation layer on the outer surface of the battery are prone to aging due to partial discharge, which may lead to a decrease in the insulation performance between the battery and the battery pack shell, which may eventually cause a short circuit and then lead to thermal runaway. It may also cause the battery pack to fail the partial discharge test and be unable to be put into use.

[0006] Utility Model Content

[0007] This application proposes a battery pack, energy storage device, and energy storage system, aiming to solve the problem of thermal runaway caused by short circuit between the battery and the battery pack casing due to partial discharge of the structural adhesive of the battery pack, as well as the problem of the battery pack failing the partial discharge test.

[0008] In a first aspect, embodiments of this application propose a battery pack, comprising: a first housing, a plurality of batteries and structural adhesive, wherein the plurality of batteries are disposed within the first housing, each battery has an insulating layer disposed on its outer surface, and the structural adhesive is disposed between the insulating layer of each battery and the bottom of the first housing, and the structural adhesive is conductive.

[0009] This embodiment proposes a battery pack in which a conductive structural adhesive is disposed between the insulating layer of each battery and the bottom of the first casing. When the battery pack is under a high electric field, even if air bubbles exist inside the structural adhesive, the conductivity of the adhesive causes charge movement within it, balancing the voltage across the adhesive and preventing high voltage differences from forming at the air bubbles. Therefore, partial discharge is prevented from forming within the air bubbles, avoiding the loss of insulation due to aging of the battery's outer insulating layer under long-term partial discharge. This prevents thermal runaway caused by a short circuit between the battery and the first casing of the battery pack, and also ensures that the battery pack passes the partial discharge test and can be put into use.

[0010] In some embodiments, the structural adhesive is an insulating material doped with a conductive medium.

[0011] In this embodiment, the structural adhesive is made of at least a conductive medium and an insulating material. During the mixing and reaction processes, bubbles will still be generated. After the structural adhesive is cured, bubbles will still exist inside. However, because the structural adhesive is conductive, under a high electric field strength, the charges in the structural adhesive will move, so that the voltage at various points in the structural adhesive will reach equilibrium. A high voltage difference will not be formed at the bubbles in the structural adhesive. Therefore, local discharge will not be formed in the bubbles of the structural adhesive.

[0012] In some embodiments, the conductive medium is a conductor material or a semiconductor material.

[0013] In this embodiment, the conductive medium doped in the insulating material can be selected based on the strength of the electric field in which the battery pack is located. If the electric field strength of the battery pack is relatively high, a conductive material can be selected to be doped in the insulating material to prepare the structural adhesive; if the electric field strength of the battery pack is relatively low, a semiconductor material can be selected to be doped in the insulating material to prepare the structural adhesive.

[0014] In some embodiments, the electrical conductivity of the structural adhesive is greater than or equal to 10. -6 S / m.

[0015] In this embodiment, this conductivity level is considered the minimum requirement for structural adhesives to be used in battery packs within a power grid. The higher the total voltage of the power grid, the stronger the electric field, and to avoid partial discharge of the battery pack, the higher the conductivity of the structural adhesive in the battery pack is required. In practical applications, structural adhesives with different conductivity levels can be selected based on the different total voltages of the power grid to ensure that the battery pack does not experience partial discharge under different electric field intensities.

[0016] In some embodiments, the thickness of the insulating layer is greater than 80 micrometers.

[0017] In this embodiment, by increasing the thickness of the insulating layer, the dielectric strength of the insulating layer is improved, enabling it to reliably withstand the voltage of the electric field without insulation breakdown and thus preventing safety accidents.

[0018] In some embodiments, the insulating layer comprises at least two sub-insulating layers. In this embodiment, multiple sub-insulating layers are provided to increase the thickness of the insulating layer.

[0019] Secondly, embodiments of this application provide an energy storage device, comprising: a second housing; a plurality of battery packs as described in the first aspect and any embodiment of the first aspect, wherein the plurality of battery packs are disposed within the second housing; and a first insulating support member disposed between the plurality of battery packs and the bottom of the second housing.

[0020] Thirdly, embodiments of this application propose an energy storage system including a plurality of energy storage devices as described in the second aspect.

[0021] The above description is merely an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0023] Figure 1 is a schematic diagram of the current battery pack structure;

[0024] Figure 2(a) is a schematic diagram of the gas inside the air bubble of the structural adhesive proposed in the embodiment of this application being ionized under the action of an electric field;

[0025] Figure 2(b) is a schematic diagram of partial discharge within the structural adhesive proposed in the embodiment of this application;

[0026] Figure 2(c) is a schematic diagram of carbonization after partial discharge in the structural adhesive proposed in the embodiment of this application;

[0027] Figure 3 is a schematic diagram of the battery pack structure proposed in an embodiment of this application;

[0028] Figure 4 is a schematic diagram of the energy storage device proposed in the embodiment of this application;

[0029] Figure 5 is a partial structural schematic diagram of the battery pack shown in Figure 1 applied to an energy storage device.

[0030] Figure 6 is a schematic diagram of the ground insulation of the energy storage device shown in Figure 5;

[0031] Figure 7 is a partial structural schematic diagram of the energy storage device shown in Figure 4;

[0032] Figure 8 is a schematic diagram of the ground insulation of the energy storage device shown in Figure 7.

[0033] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0034] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0035] 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 application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0036] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0037] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0038] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0039] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0040] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0041] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0042] The battery pack consists of multiple batteries connected in series, parallel, or in a series-parallel configuration. Each battery is fixed to the bottom of the battery pack casing with structural adhesive, which serves the dual purpose of fixing the battery and insulating it from the ground.

[0043] Due to the characteristics and process limitations of structural adhesives, it is difficult to completely eliminate the presence of air bubbles inside after the structural adhesive has cured. When the battery pack is under a high electric field strength, the air bubbles inside the structural adhesive may become the starting point of partial discharge. The structural adhesive and even the insulation layer on the outer surface of the battery are prone to aging due to partial discharge, which may lead to a decrease in the insulation performance between the battery and the battery pack shell, which may eventually cause a short circuit and then lead to thermal runaway. It may also cause the battery pack to fail the partial discharge test and be unable to be put into use.

[0044] In response to this, this application proposes a battery pack comprising: a first housing, a plurality of batteries and structural adhesive, wherein the plurality of batteries are disposed within the first housing, each battery having an insulating layer disposed on its outer surface, and the structural adhesive being disposed between the insulating layer of each battery and the bottom of the first housing, and the structural adhesive being conductive.

[0045] In this embodiment, a conductive structural adhesive is disposed between the insulating layer of each battery and the bottom of the first casing. When the battery pack is under a high electric field strength, even if air bubbles exist inside the structural adhesive, due to the conductivity of the structural adhesive, the charges within the structural adhesive move under the high electric field strength, causing the voltage at various points within the structural adhesive to reach equilibrium. This prevents the formation of a high voltage difference at the air bubbles in the structural adhesive, thus preventing partial discharge from forming within the air bubbles. This avoids the insulating layer on the outer surface of the battery losing its insulating function due to aging under the long-term effects of partial discharge, thereby preventing thermal runaway caused by a short circuit between the battery and the first casing of the battery pack. It also ensures that the battery pack can pass the partial discharge test and be put into use.

[0046] To better understand the embodiments of this application, the battery pack, energy storage device, and energy storage system provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0047] Figure 1 shows a schematic diagram of a battery pack 10. The battery pack 10 includes: a first housing 101, a plurality of batteries 102 disposed inside the first housing 101, an insulating layer 103 disposed on the outer surface of each battery 102, and an insulating structural adhesive 104 disposed between the insulating layer 103 of each battery 102 and the bottom of the first housing 101. The insulating structural adhesive 104 serves the dual function of fixing the batteries 102 and insulating them from the ground.

[0048] The components of insulating structural adhesive 104 typically include resin and curing agent, and may also include fillers to improve the thermal conductivity of insulating structural adhesive 104. Since insulating structural adhesive 104 is prepared by mixing multiple materials, air bubbles 1040 are easily formed during the mixing and reaction processes. Therefore, it is difficult to completely eliminate the presence of air bubbles 1040 inside the insulating structural adhesive 104 after curing, as shown in Figure 1 where multiple air bubbles 1040 are present inside the insulating structural adhesive 104.

[0049] Research has shown that battery pack 10 can be used in electric vehicles, electric bicycles, etc. The total voltage of battery pack 10 is generally several hundred volts, and the electric field strength of battery pack 10 is not high, so partial discharge of the insulating adhesive 104 will not occur. However, when battery pack 10 is used in the power grid, the total voltage of battery pack 10 is generally in the kilovolt range, or even as high as several hundred kilovolts, and the electric field strength of battery pack 10 is high.

[0050] When the battery pack 10 is under a high electric field, the bubbles 1040 inside the insulating structural adhesive 104 may become the starting point of partial discharge. This is because the dielectric constant of the bubbles 1040 in the insulating structural adhesive 104 is much lower than that of the surrounding insulating material, and the bubble 1040 region will exhibit a lower dielectric strength. Under a high electric field, the electric field strength near the bubbles 1040 is much higher than that in the insulating material. The gas inside the bubbles 1040 is ionized under the action of the electric field, forming electrons and positive ions, as shown in Figure 2(a). These charged particles are accelerated under the action of the electric field, which may further ionize gas molecules, forming a chain reaction. The space charge generated by ionization will form a local electric field inside the bubbles 1040. This local electric field will be superimposed on the external electric field, causing the electric field inside the bubbles 1040 to be further enhanced, thereby promoting more ionization. Once the voltage difference of the local electric field inside the bubbles 1040 reaches a certain level, partial discharge will occur, as shown in Figure 2(b). This discharge typically manifests as tiny electric sparks, which cause the gas temperature inside the bubble 1040 to rise, further intensifying the ionization process. At the same time, the tiny electric sparks can also burn the insulating structural adhesive 104 and even the insulating layer 103 on the outer surface of the battery 102, causing it to carbonize. As shown in Figure 2(c), the carbonization process can be regarded as the aging process of the insulating structural adhesive 104 and the insulating layer 103, which leads to a decrease in the insulation performance between the battery 102 and the battery pack 10 shell, which may eventually cause a short circuit, leading to thermal runaway. It may also cause the battery pack 10 to fail the partial discharge test, making the battery pack 10 unusable.

[0051] In response to this, this embodiment provides a battery pack 10, as shown in FIG3, including: a first housing 101, a plurality of batteries 102 disposed inside the first housing 101, an insulating layer 103 disposed on the outer surface of each battery 102, and a structural adhesive 105 disposed between the insulating layer 103 of each battery 102 and the bottom of the first housing 101, and the structural adhesive 105 is conductive.

[0052] The number of batteries 102 in the battery pack 10 in Figure 3 is three, which is only for illustrative purposes. In practice, the number of batteries 102 in the battery pack 10 can be set as needed. The multiple batteries 102 shown in Figure 3 are connected in series, which is only for illustrative purposes. In practice, multiple batteries 102 can be connected in series, in parallel, or in a series-parallel connection.

[0053] An insulating layer 103 is provided on the outer surface of each battery 102. The insulating layer 103 is directly disposed on the outer surface of the battery 102 and serves to insulate between the batteries 102. The insulating layer 103 can be made of a single insulating material (such as polyimide) without the addition of other materials. Therefore, the insulating layer 103 does not contain air bubbles 1040.

[0054] A conductive structural adhesive 105 replaces the insulating structural adhesive 104 shown in Figure 1. The conductive structural adhesive 105 is disposed between the insulating layer 103 of each battery 102 and the bottom of the first housing 101, serving to fix the battery 102 and conduct electricity. When the battery pack 10 is applied to the power grid, under high electric field strength, even if there are air bubbles 1040 inside the structural adhesive 105, due to the conductivity of the structural adhesive 105, the charges within the structural adhesive 105 move, causing the voltage at various points within the structural adhesive 105 to reach equilibrium. A high voltage difference will not form at the air bubbles 1040 of the structural adhesive 105. Therefore, partial discharge will not form in the air bubbles 1040 of the structural adhesive 105. This prevents the insulating layer 103 on the outer surface of the battery 102 from losing its insulating function due to aging under the long-term effects of partial discharge, thereby preventing thermal runaway caused by a short circuit between the battery 102 and the first housing 101 of the battery pack 10. It also ensures that the battery pack 10 can pass the partial discharge test and be put into use.

[0055] The conductive structural adhesive 105 will be described in detail below.

[0056] In some embodiments, the structural adhesive 105 is made of an insulating material doped with a conductive medium.

[0057] Structural adhesive 105 can use insulating materials as the base material, that is, non-conductive adhesives, such as epoxy resin, silicone rubber, polyurethane, etc. To make these insulating materials conductive, conductive media are added to them. Additionally, if epoxy resin or polyurethane is used as the insulating material, a curing agent needs to be added to the insulating material to allow structural adhesive 105 to cure. If silicone rubber is used as the insulating material, a curing agent is not required.

[0058] In this embodiment, the structural adhesive 105 is made of at least a conductive medium and an insulating material. During the mixing and reaction processes, bubbles will still be generated. After the structural adhesive 105 is cured, bubbles will still exist inside (not shown in the figure). However, since the structural adhesive 105 is conductive, under a high electric field strength, the charge in the structural adhesive 105 will move, so that the voltage at various points in the structural adhesive 105 will reach equilibrium. A high voltage difference will not be formed at the bubbles (not shown in the figure) of the structural adhesive 105. Therefore, partial discharge will not be formed in the bubbles (not shown in the figure) of the structural adhesive 105.

[0059] In some embodiments, the conductive medium is a conductor material or a semiconductor material.

[0060] Conductive materials include: metal powders (such as silver, copper, nickel, aluminum, etc.), metal fibers (such as copper fibers, nickel fibers, etc.), carbon materials (such as carbon black, graphite, carbon nanotubes, graphene, etc.), and conductive polymers (such as polyaniline, polythiophene, etc.). Structural adhesive 105, which uses conductive materials as the conductive medium, possesses conductor properties, with a conductivity reaching 10⁻⁶. 4 S / m (Siemens / meter) or higher.

[0061] Semiconductor materials include, for example, silicon (usually added to the adhesive in the form of silicon particles or wafers), zinc oxide, and other semiconductor materials (such as gallium arsenide, indium phosphide, etc.). Structural adhesive 105, which uses semiconductor materials as the conductive medium, possesses semiconductor properties, with a conductivity of up to 10⁻⁶. -6 S / m to 10 3 S / m (Siemens meter).

[0062] In practical applications, the conductive medium doped in the insulating material can be selected based on the strength of the electric field at which the battery pack 10 is located. If the electric field at which the battery pack 10 is located is relatively strong, a conductive material can be selected to be doped in the insulating material to prepare the structural adhesive 105; if the electric field at which the battery pack 10 is located is relatively weak, a semiconductor material can be selected to be doped in the insulating material to prepare the structural adhesive 105.

[0063] In some embodiments, the electrical conductivity of the structural adhesive 105 is greater than or equal to 10. -6 S / m.

[0064] Structural adhesive 105 has an electrical conductivity greater than or equal to 10. -6 S / m (Siemens per meter) indicates that the structural adhesive 105 has relatively good conductivity. This conductivity level is considered the minimum requirement for structural adhesive 105 to be used in battery pack 10 in the power grid. The higher the total voltage of the power grid, the stronger the electric field. To avoid partial discharge in battery pack 10, the conductivity of structural adhesive 105 in battery pack 10 also needs to be higher. In practical applications, structural adhesive 105 with different conductivity can be selected according to different total voltages of the power grid to ensure that battery pack 10 does not partially discharge under different electric field strengths.

[0065] The material of the structural adhesive 105 in the above embodiment is only an example. In practical applications, other materials can also be used to prepare conductive structural adhesive 105, as long as the conductivity of the structural adhesive 105 can meet the requirements of avoiding partial discharge. This embodiment will not elaborate on these points.

[0066] The insulating layer 103 disposed on the outer surface of the battery 102 will be described in detail below.

[0067] As shown in Figure 1, in an electric field, the insulating layer 103 and the insulating structural adhesive 104 on the outer surface of the battery 102 jointly bear the voltage of the electric field. However, in the battery pack 10 of this embodiment shown in Figure 3, a conductive structural adhesive 105 is used. In an electric field, the conductive structural adhesive 105 bears part or almost no voltage, with most of the voltage being borne by the insulating layer 103 on the outer surface of the battery 102. Therefore, in the same electric field, the voltage borne by the insulating layer 103 on the outer surface of the battery 102 shown in Figure 3 is greater than the voltage borne by the insulating layer 103 on the outer surface of the battery 102 shown in Figure 1. Therefore, in order for the insulating layer 103 on the outer surface of the battery 102 shown in Figure 3 to reliably bear the voltage of the electric field without insulation breakdown and causing a safety accident, the dielectric strength of the insulating layer 103 on the outer surface of the battery 102 shown in Figure 3 must be greater than the dielectric strength of the insulating layer 103 on the outer surface of the battery 102 shown in Figure 1.

[0068] In some embodiments, the thickness of the insulating layer 103 is greater than 80 micrometers.

[0069] The thickness of the insulating layer 103 shown in Figure 1 is generally less than or equal to 80 micrometers. In this embodiment, the insulating layer 103 with a thickness greater than 80 micrometers can be used in Figure 3. By increasing the thickness of the insulating layer 103 in Figure 3, the dielectric strength of the insulating layer 103 can be improved.

[0070] It is feasible that the thickness of the insulating layer 103 in Figure 3 can also be 90 micrometers, 100 micrometers, etc. The thickness of the insulating layer 103 can be selected according to the magnitude of the electric field voltage borne by the insulating layer 103. The larger the electric field voltage borne by the insulating layer 103, the thicker the insulating layer 103 needs to be.

[0071] In some embodiments, the insulating layer 103 comprises at least two sub-insulating layers.

[0072] The thickness of insulation layer 103 can be increased by setting multiple sub-insulating layers. In practical applications, the insulation layer 103 shown in Figure 1 can be used as a sub-insulating layer in the insulation layer 103 in Figure 3, and the insulation performance of the insulation layer 103 in Figure 3 can be improved by setting multiple sub-insulating layers.

[0073] In some embodiments, the conductivity of the insulating layer 103 in this embodiment is less than or equal to 10. -16 S / m.

[0074] The conductivity of the insulating layer 103 shown in Figure 1 is generally around 10. -14 S / m (Siemens / meter), in this embodiment, the conductivity of the insulating layer 103 in Figure 3 is less than or equal to 10. -16 With a strength of S / m (Siemens per meter), it has better insulation performance and dielectric strength, thus it can reliably withstand the voltage of the electric field without insulation breakdown and causing safety accidents.

[0075] In practical applications, the insulation layer 103 with different conductivity can be selected according to the magnitude of the electric field voltage borne by the insulation layer 103. The larger the electric field voltage borne by the insulation layer 103, the better the insulation performance of the insulation layer 103 needs to be, and the smaller the conductivity of the insulation layer 103 needs to be.

[0076] It is possible that the insulating layer 103 in Figure 3 can be made of a material with better insulating properties than the insulating layer 103 in Figure 1. For example, the insulating layer 103 shown in Figure 1 is made of polyimide, which typically has an electrical conductivity of 10⁻⁶. -15 Up to 10 -13 Within the range of S / m (Siemens per meter); the insulating layer 103 shown in Figure 3 can be made of materials with better insulation properties than polytetrafluoroethylene, epoxy resin, polyethylene, polypropylene, etc., where polytetrafluoroethylene typically has an electrical conductivity of 10. -22 S / m to 10 -20 S / m, the conductivity of epoxy resin is typically around 10. -16 S / m to 10 -15 S / m, the electrical conductivity of polyethylene is typically around 10. -17 S / m to 10 -16 S / m, the conductivity of polypropylene is typically around 10. -16 S / m to 10 -15 S / m. By using a material with better insulation properties to prepare the insulating layer 103 in Figure 3, the conductivity of the insulating layer 103 in Figure 3 is reduced.

[0077] It is possible that the insulating layer 103 in Figure 3 can be made of the same insulating material as the insulating layer 103 in Figure 1, but the thickness of the insulating layer 103 in Figure 3 is greater than the thickness of the insulating layer 103 in Figure 1.

[0078] For example, the thickness of the insulating layer 103 shown in Figure 1 is generally less than or equal to 80 micrometers. In this embodiment, the insulating layer 103 in Figure 3 can have a thickness greater than 80 micrometers, such as 90 micrometers or 100 micrometers. By increasing the thickness of the insulating layer 103 in Figure 3, the conductivity of the insulating layer 103 in Figure 3 is reduced.

[0079] To achieve the above objectives, this application also proposes an energy storage device 20, as shown in FIG4. The energy storage device 20 includes: a second housing 201, a plurality of battery packs 10 as described in the above embodiments, the plurality of battery packs 10 being disposed within the second housing 201; and a first insulating support member 202, the first insulating support member 202 being disposed between the plurality of battery packs 10 and the bottom of the second housing 201.

[0080] In Figure 4, the energy storage device 20 contains two battery packs 10, which is only for illustrative purposes. In practice, the number of battery packs 10 in the energy storage device 20 can be set as needed. The multiple battery packs 10 shown in Figure 4 are connected in series, which is only for illustrative purposes. In practice, multiple battery packs 10 can be connected in series, in parallel, or in a series-parallel connection.

[0081] The first insulating support 202 is disposed between the bottom of the plurality of battery packs 10 and the second housing 201, and serves to insulate and fix the battery packs 10.

[0082] It is worth noting that the energy storage device 20 is not placed directly on the ground 40, but is fixed to the ground 40 by the second insulating support 30.

[0083] Figure 5 shows a partial structural schematic diagram of the energy storage device 20 composed of the battery pack 10 shown in Figure 1. The resistance of the insulating layer 103 on the outer surface of the battery 102 is R1 and the capacitance is C1. The resistance of the insulating structural adhesive 104 is R2 and the capacitance is C2. The resistance of the first shell 101 and the first insulating support 202 is R3 and the capacitance is C3. The resistance of the second shell 201 and the second insulating support 30 is R4. The capacitance of the second shell 201 to ground is C4. The resistance of the first shell 101 to ground is R5.

[0084] Figure 6 shows a schematic diagram of the ground insulation of the energy storage device 20 shown in Figure 5. In the electric field, the resistance R1 and capacitance C1 of the insulating layer 103 on the outer surface of the battery 102, the resistance R2 and capacitance C2 of the insulating structural adhesive 104, the resistance R3 and capacitance C3 of the first shell 101 and the first insulating support 202, the resistance R4 of the second shell 201 and the second insulating support 30, the capacitance C4 of the second shell 201 to ground, and the resistance R5 of the first shell 101 to ground together bear the voltage in the electric field.

[0085] Figure 7 shows a partial structural schematic diagram of the energy storage device 20 in Figure 4. The battery pack 10 uses a conductive structural adhesive 105. Assuming that the conductive structural adhesive 105 has good conductivity and does not bear voltage, the ground insulation schematic diagram of the energy storage device 20 shown in Figure 7 is shown in Figure 8. The resistance R1 and capacitance C1 of the insulating layer 103 on the outer surface of the battery 102, the resistance R3 and capacitance C3 of the first shell 101 and the first insulating support 202, the resistance R4 of the second shell 201 and the second insulating support 30, the capacitance C4 of the second shell 201 to ground, and the resistance R5 of the first shell 101 to ground together bear the voltage in the electric field. Assuming the voltage of the electric field remains constant, the voltage originally borne by the resistor R2 and capacitor C2 of the insulating structural adhesive 104 in Figure 6 is now borne by other parts. Therefore, in practical applications, the insulation performance of at least one of the insulating layer 103, the first shell 101, the first insulating support 202, and the second insulating support 30 on the outer surface of the battery 102 can be appropriately enhanced to ensure that the energy storage device 20 can reliably withstand the voltage of the electric field without being damaged.

[0086] To achieve the above objectives, this application also proposes an energy storage system, which includes a plurality of energy storage devices 20 as described in the above embodiments.

[0087] The output of a single energy storage device 20 is connected to a power conversion system, which is connected to the power grid. The output of the single energy storage device 20 is direct current (DC), which is converted to alternating current (AC) by the power conversion system and then connected to the power grid to supply power to the grid; or, the power grid converts AC to DC through the power conversion system to charge the energy storage device 20.

[0088] The above are merely preferred embodiments of this application and do not limit the scope of the patent application. Any equivalent structural transformations made based on the inventive concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the scope of patent protection of this application.

Claims

1. A battery pack, wherein, include: First shell; Multiple batteries, each of which has an insulating layer on its outer surface, are disposed within the first housing; A structural adhesive, disposed between the insulating layer of each battery and the bottom of the first housing, is conductive.

2. The battery pack as claimed in claim 1, wherein, The structural adhesive is made of an insulating material doped with a conductive medium.

3. The battery pack as described in claim 2, wherein, The conductive medium is a conductor material or a semiconductor material.

4. The battery pack as described in claim 3, wherein, The conductor material is any one of the following: metal powder, metal fiber, carbon material, or conductive polymer.

5. The battery pack as described in claim 3, wherein, The semiconductor material is any one of the following: silicon, zinc oxide, gallium arsenide, or indium phosphide.

6. The battery pack as claimed in any one of claims 2 to 5, wherein, The insulating material is any one of the following: epoxy resin, silicone rubber, or polyurethane.

7. The battery pack as claimed in any one of claims 1 to 6, wherein, The structural glue has an electrical conductivity greater than or equal to 10 -6 S / m.

8. The battery pack as claimed in claim 7, wherein, In the case that the conductive medium of the structural adhesive is a conductor material, the conductivity of the structural adhesive is greater than 10 4 S / m.

9. The battery pack as claimed in claim 7, wherein, In the case that the conductive medium of the structural adhesive is a semiconductor material, the conductivity of the structural adhesive is between 10 -6 S / m ~ 10 3 S / m.

10. The battery pack according to any one of claims 1 to 8, wherein, The thickness of the insulating layer is greater than 80 micrometers.

11. The battery pack of claim 10, wherein, The insulating layer comprises at least two sub-insulating layers.

12. The battery pack as claimed in any one of claims 1 to 11, wherein, The electrical conductivity of the insulating layer is less than or equal to 10. -16 S / m.

13. An energy storage device, wherein, include: Second shell; Multiple battery packs as described in any one of claims 1 to 12, wherein the multiple battery packs are disposed within the second housing; A first insulating support is disposed between the bottom of the plurality of battery packs and the second housing.

14. The energy storage device as claimed in claim 13, wherein, It also includes a second insulating support member, which is disposed at the bottom of the second housing and is used to fix the energy storage device to the ground.

15. An energy storage system, wherein, It includes multiple energy storage devices as described in claim 13 or 14.

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