Battery Pack and Energy Storage System

Abstract

The present disclosure relates to a battery pack and an energy storage system, and relates to the field of energy storage technology. The battery pack includes: a battery case, a plurality of battery modules and a conductive connecting piece, the battery case is formed with a battery compartment; the plurality of battery modules are located in the battery compartment; the plurality of battery modules include a first battery module and a second battery module, the first battery module is provided with a first output pole base and a first output pole connecting piece, the second battery module is provided with a second output pole base and a second output pole connecting piece; the first connecting portion of the conductive connecting piece is located on the first output pole base and connected to the first output pole connecting piece, the second connecting portion is located on the second output pole base and connected to the second output pole connecting piece, an insulating layer is provided on the surface of the middle connecting portion, and the insulating layer has an overlapping portion with the first output pole base and the second output pole base. In the battery pack provided by the present disclosure, an insulating layer is provided on the conductive connecting piece, which improves the insulation performance between the conductive connecting piece and the end plate.

Description

Technical Field

[0001] The present disclosure relates to the field of energy storage technology, and in particular to a battery pack and an energy storage system. Background Art

[0002] A battery pack usually includes multiple battery modules, and multiple battery modules usually need to be electrically connected. When connecting sheets are used to achieve electrical connection between battery modules, since the end plates at both ends of the battery module are usually metal end plates that need to be insulated, there is a risk of short circuit between the connecting sheets and the end plates, which seriously affects the safety performance of the battery pack.

[0003] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0004] The purpose of the present disclosure is to provide a battery pack and an energy storage system.

[0005] According to one aspect of the present disclosure, a battery pack is provided, the battery pack comprising:

[0006] A battery box, wherein the battery box is formed with a battery compartment;

[0007] A plurality of battery modules, wherein the plurality of battery modules are located in the battery compartment; each of the battery modules comprises a plurality of battery cells arranged along a first direction and end plates clamped at both ends of the plurality of battery cells; the plurality of battery modules comprises at least a first battery module and a second battery module arranged adjacent to each other along the first direction, a first end plate adjacent to the second battery module in the first battery module is provided with an insulating first output pole base, and a first output pole connecting piece is provided on the battery cell adjacent to the first end plate; a second end plate adjacent to the first battery module in the second battery module is provided with an insulating second output pole base, and a second output pole connecting piece is provided on the battery cell adjacent to the second end plate;

[0008] A conducting connecting piece, the conducting connecting piece comprising a first connecting portion, a second connecting portion and an intermediate connecting portion located between the first connecting portion and the second connecting portion, the first connecting portion being located on the first output pole base and connected to the first output pole connecting piece, the second connecting portion being located on the second output pole base and connected to the second output pole connecting piece;

[0009] An insulating layer is provided on the surface of the intermediate connecting portion, and the insulating layer has an overlapping portion with the first output pole base and the second output pole base along the first direction.

[0010] In the battery pack provided by the present invention, the two ends of the conductive connecting piece are respectively located on the first output pole base and the second output pole base, thereby achieving insulation between the first end plate and the second end plate; an insulating layer is provided on the surface of the intermediate connecting portion, which can insulate the surface of the conductive connecting piece exposed between the first end plate and the second end plate, so that the creepage path between the conductive connecting piece and the first end plate and the second end plate needs to pass through the insulating layer to the side plate of the output pole base, and then to the exposed first end plate and the second end plate, thereby increasing the creepage distance between the original energized conductive connecting piece and the exposed surface of the first end plate and the second end plate, thereby improving the creepage short circuit phenomenon between the conductive connecting piece and the first end plate and the second end plate; at the same time, the edge position of the insulating layer is moved inward to the inner side of the first output pole base, and in the event that the first battery module and the second battery module expand and displace and stretch the conductive connecting piece, the creepage distance between the conductive connecting piece and the first end plate and the second end plate is guaranteed to be within the insulation safety range to the greatest extent, thereby avoiding safety accidents caused by short circuits and improving the safety performance of the battery pack.

[0011] In an exemplary embodiment of the present disclosure, at least a portion of the intermediate connecting portion is in a bent structure, and the first connecting portion and the second connecting portion can move away from or towards each other along the first direction through the bent structure.

[0012] The battery pack provided in this embodiment is provided with a bending structure. When the conductive connecting piece is subjected to a tensile force, the bending structure can absorb the tensile force, thereby preventing the conductive connecting piece from being deformed or even broken.

[0013] In an exemplary embodiment of the present disclosure, when the first connecting portion and the second connecting portion move away from each other along the first direction so that the middle connecting portion with the bent structure is in a straight state, the insulating layer has an overlapping portion with the first output pole base and the second output pole base in the first direction.

[0014] In the battery pack provided by the present embodiment, when the first battery module and the second battery module expand and displace to stretch the conductive connecting piece, when the middle connecting portion of the bent structure is in a straight state, the insulating layer and the first output pole base and the second output pole base still have an overlapping portion, thereby ensuring to the greatest extent that the creepage distance between the conductive connecting piece and the first end plate and the second end plate is within the insulation safety range, avoiding safety accidents caused by short circuits, and improving the safety performance of the battery pack.

[0015] In an exemplary embodiment of the present disclosure, the insulating layer is made of an elastic material, and when the first connecting portion and the second connecting portion move away from or toward each other along the first direction, the insulating layer made of the elastic material can stretch or shrink.

[0016] The battery pack provided in the present embodiment can better adhere to the surface of the conductive connecting piece through the insulating layer of elastic material to improve the insulation performance of the conductive connecting piece; at the same time, when the first battery module and the second battery module expand and displace to stretch the conductive connecting piece, the conductive connecting piece can be stretched along with the stretching of the conductive connecting piece, thereby avoiding cracks in the insulating layer that expose the charged metal surface of the middle connecting part, thereby avoiding affecting the insulation performance between the conductive connecting piece and the end plate.

[0017] In an exemplary embodiment of the present disclosure, the insulating layer is bonded to the conductive connection sheet.

[0018] In the battery pack provided in this embodiment, the insulating layer is bonded to the conductive connecting piece by bonding, so that the insulating layer is conveniently provided on the conductive connecting piece; at the same time, it is convenient to bond and cover the part of the conductive connecting piece that needs to be insulated according to actual needs.

[0019] In an exemplary embodiment of the present disclosure, the insulating layer is an insulating tape.

[0020] The battery pack provided in this embodiment uses insulating tape to facilitate the arrangement of the insulating layer on the conductive connecting piece. The insulating tape has good elasticity and can be tightly attached to the surface of the conductive connecting piece by bonding. The insulating tape can be wrapped around the portion of the conductive connecting piece that needs to be insulated for multiple turns to improve the insulation effect and prevent the insulating layer from being easily pierced when the thickness is relatively thin.

[0021] In an exemplary embodiment of the present disclosure, the first output pole base is arranged on one side of the first end plate along the second direction, and the first output pole base is provided with a first extension portion extending toward the one side of the first end plate, and the first extension portion and the first end plate have an overlapping portion in the second direction; and / or, the second output pole base is arranged on one side of the second end plate along the second direction, and the second output pole base is provided with a second extension portion extending toward the one side of the second end plate, and the second extension portion and the second end plate have an overlapping portion in the second direction.

[0022] The battery pack provided in this embodiment blocks the portion of the conductive connection sheet directly below and closest to the first end plate by the first extension portion, that is, increases the distance between the live conductive connection sheet and the first end plate, so that the battery cell can better ensure the insulation between the first end plate and the live conductive connection sheet in both operating and non-operating conditions, thereby preventing a short circuit between the two. The portion of the conductive connection sheet directly below and closest to the second end plate is blocked by the second extension portion, that is, increases the distance between the live conductive connection sheet and the second end plate, so that the battery cell can better ensure the insulation between the second end plate and the live conductive connection sheet in both operating and non-operating conditions, thereby preventing a short circuit between the two.

[0023] In an exemplary embodiment of the present disclosure, the first output pole base is arranged on one side of the first end plate along the second direction, and the first output pole base is provided with first side plates extending toward the second direction on both sides along the third direction; in the second direction, the height of the first side plate is greater than the thickness of the first connecting portion; and / or, the second output pole base is arranged on one side of the second end plate along the second direction, and the second output pole base is provided with second side plates extending toward the second direction on both sides along the third direction; in the second direction, the height of the second side plate is greater than the thickness of the second connecting portion;

[0024] The third direction intersects with the first direction and the second direction.

[0025] The battery pack provided in this embodiment can increase the creepage distance between the conductive connecting piece in the first output pole base and the first end plate directly below it by increasing the height of the first side plate, thereby preventing the creepage phenomenon between the two from being reduced due to the presence of pollutants such as suspended dust or charged particles in the air around the first output pole base during use of the battery pack; and can increase the creepage distance between the conductive connecting piece in the second output pole base and the second end plate directly below it by increasing the height of the second side plate, thereby preventing the creepage phenomenon between the two from being reduced due to the presence of pollutants such as suspended dust or charged particles in the air around the second output pole base during use of the battery pack.

[0026] In an exemplary embodiment of the present disclosure, when the first side panel is provided on the first output pole base, the first side panel is provided with a first extension portion extending along the first direction toward one side of the second end plate, and the first extension portion protrudes from the first end plate in the first direction; and / or, when the second side panel is provided on the second output pole base, the second side panel is provided with a second extension portion extending along the second direction toward one side of the first end plate, and the second extension portion protrudes from the second end plate in the first direction.

[0027] The battery pack provided in this embodiment extends to the outside of the first end plate through the first extension portion on the first side plate, thereby increasing the distance between the live conductive connecting piece and the first end plate, so that the battery cell can better ensure the insulation between the first end plate and the live conductive connecting piece in both operating and non-operating conditions, thereby preventing the occurrence of a short circuit between the two; and extends to the outside of the second end plate through the second extension portion on the second side plate, thereby increasing the distance between the live conductive connecting piece and the second end plate, so that the battery cell can better ensure the insulation between the first end plate and the live conductive connecting piece in both operating and non-operating conditions, thereby preventing the occurrence of a short circuit between the two.

[0028] In an exemplary embodiment of the present disclosure, the first output pole base includes a first base located between the first connecting portion and the first end plate, the first base is provided with a first protrusion extending along the first direction toward one side of the second end plate, and the first protrusion protrudes from the first end plate in the first direction; and / or, the second output pole base includes a second base located between the second connecting portion and the second end plate, the second base is provided with a second protrusion extending along the first direction toward one side of the first end plate, and the second protrusion protrudes from the second end plate in the first direction.

[0029] In the battery pack provided in this embodiment, the first protrusion protrudes to the top outer side of the first end plate, increasing the distance between the charged first protrusion and the exposed first end plate, so that the battery cell can better ensure the insulation between the first end plate and the charged conductive connecting piece both in operating and non-operating conditions; the second protrusion protrudes to the top outer side of the second end plate, increasing the distance between the charged second protrusion and the exposed second end plate, so that the battery cell can better ensure the insulation between the second end plate and the charged conductive connecting piece both in operating and non-operating conditions.

[0030] In an exemplary embodiment of the present disclosure, the battery pack further includes:

[0031] A first transition connecting piece and a second transition connecting piece, wherein the first transition connecting piece is located on the first output pole base and connected to the first output pole connecting piece, and the resistance of the first transition connecting piece is smaller than the resistance of the first output pole connecting piece; the second transition connecting piece is located on the second output pole base and connected to the second output pole connecting piece, and the resistance of the second transition connecting piece is smaller than the resistance of the second output pole connecting piece; the first end of the conductive connecting piece is connected to the first transition connecting piece, and the second end is connected to the second transition connecting piece.

[0032] In the battery pack provided by the present embodiment, since the resistance of the first transition connecting piece is smaller than the resistance of the first output pole connecting piece, and the resistance of the second transition connecting piece is smaller than the resistance of the second output pole connecting piece, the overcurrent capacity of the corresponding electrical connectors on the first output pole base and the second output pole base is improved, thereby avoiding the problem that the overcurrent capacity is relatively low after the first output pole connecting piece is located on the first output pole base and the second output pole connecting piece is located on the second output pole base, which causes the output pole connecting piece to easily heat up severely, fuse, and cause electrical connection failure.

[0033] In an exemplary embodiment of the present disclosure, a first protrusion is provided on one of the first transition connecting piece and the conducting connecting piece, and a first recess is provided on the other, and the first protrusion is located in the first recess; and / or a second protrusion is provided on one of the second transition connecting piece and the conducting connecting piece, and a second recess is provided on the other, and the second protrusion is located in the second recess.

[0034] The battery pack provided in this embodiment has a raised portion and a recessed portion which cooperate to position the transition connecting piece and the conductive connecting piece during assembly, so that the staff can pre-position the transition connecting piece and the copper busbar when fixing them to the module, thereby speeding up the installation and alignment of the fixing bolts and improving production efficiency.

[0035] In an exemplary embodiment of the present disclosure, the outer circumferential dimension of the first recessed portion is greater than the outer circumferential dimension of the first protruding portion, and in the direction in which the first transition connecting piece and the conductive connecting piece are stacked, the diameter of the first protruding portion decreases toward the first recessed portion, and the height of the first protruding portion is greater than the depth of the first recessed portion; and / or, the outer circumferential dimension of the second recessed portion is greater than the outer circumferential dimension of the second protruding portion, and in the direction in which the second transition connecting piece and the conductive connecting piece are stacked, the diameter of the second protruding portion decreases toward the second recessed portion, and the height of the second protruding portion is greater than the depth of the second recessed portion.

[0036] In the battery pack provided by the present embodiment, the outer circumferential dimension of the recessed portion is larger than that of the raised portion, and a certain assembly gap / margin is reserved, which reduces the operating accuracy of the operator and speeds up production efficiency; at the same time, the raised portion has a large bottom and a small head structure, and the height of the raised portion along the height direction is greater than the depth of the recessed portion. The large bottom and small head facilitate the insertion of the raised portion into the recessed portion, which has a guiding effect. Since the bolt threading will have a downward force pressing connection, the raised portion will deform and fill the recessed portion during the pressing process, so that the conductive connecting piece and the transition connecting piece can be closely matched, thereby improving the structural stability; further, the close match between the raised portion and the recessed portion can increase the electrical connection area between the transition connecting piece and the conductive connecting piece, improve the current passing capacity, reduce heat, and avoid thermal safety accidents.

[0037] In an exemplary embodiment of the present disclosure, a first through hole is provided on the conductive connecting piece, a second through hole is provided on the first transition connecting piece, the first transition connecting piece and the conductive connecting piece are fixed to the first end plate by passing through the first through hole and the second through hole by a first screw member, and the diameter of the first through hole is greater than the diameter of the second through hole; and / or, a third through hole is provided on the conductive connecting piece, a fourth through hole is provided on the second transition connecting piece, the second transition connecting piece and the conductive connecting piece are fixed to the second end plate by passing through the third through hole and the fourth through hole by a second screw member, and the diameter of the third through hole is greater than the diameter of the fourth through hole.

[0038] The battery pack provided in this embodiment has a large via hole on the conductive connecting piece and a small via hole on the transition connecting piece below. This makes it easy to intuitively see whether the smaller via hole on the transition connecting piece is aligned through the larger via hole on the conductive connecting piece when the raised portion and the recessed portion of the conductive connecting piece and the transition connecting piece are matched, thereby reducing operation accuracy and improving production efficiency.

[0039] In an exemplary embodiment of the present disclosure, the first recessed portion is provided on the first transition connecting piece, and the first protruding portion is provided on the conductive connecting piece; the first protruding portion surrounds the first via hole, and the portion of the conductive connecting piece surrounding the first via hole protrudes toward one side of the first transition connecting piece, the first protruding portion is formed on the side facing the first transition connecting piece, and a first sinking platform is formed on the side facing away from the first transition connecting piece, and the first threaded member is located in the first sinking platform; and / or, the second recessed portion is provided on the second transition connecting piece, and the conductive connecting piece is provided with the second protruding portion; the second protruding portion surrounds the third via hole, and the portion of the conductive connecting piece surrounding the third via hole protrudes toward one side of the second transition connecting piece, the second protruding portion is formed on the side facing the second transition connecting piece, and a second sinking platform is formed on the side facing away from the second transition connecting piece, and the second threaded member is located in the second sinking platform.

[0040] In the battery pack provided in this embodiment, a sink is provided on the side of the conductive connecting piece facing away from the transition connecting piece, which can reduce the height of the bolts on the output pole base; since the bolts at the end plate are not charged and the bolts on the output pole base are charged, the creepage distance between the two must pass through the side plate of the output pole base. By reducing the height of the bolts at the output pole base, the creepage distance between the bolts on the output pole base and the bolts fixing the end plate can be increased, thereby avoiding a short circuit between the conductive connecting piece and the end plate, and improving the safety performance of the battery.

[0041] In an exemplary embodiment of the present disclosure, the multiple battery modules include multiple groups of the first battery modules and the second battery modules, and the multiple groups of the first battery modules and the second battery modules are arranged along a third direction; the first battery modules and the second battery modules in each group are connected through the conductive connecting piece; wherein the first output pole base is located on one side of the first end plate along the second direction, and the third direction intersects with the first direction and the second direction.

[0042] In the battery pack provided in this embodiment, the first battery module and the second battery module in each group are connected via the conductive connecting piece, which can further improve the safety performance of the battery pack.

[0043] According to another aspect of the present disclosure, there is also provided an energy storage system, which includes the battery pack described in any of the above embodiments.

[0044] In the energy storage system provided by the present disclosure, the two ends of the conductive connecting piece in the battery pack are respectively located on the first output pole base and the second output pole base, thereby achieving insulation between the first end plate and the second end plate; at the same time, the middle connecting part on the conductive connecting piece is located between the first end plate and the second end plate, and an insulating layer is provided on the surface of the middle connecting part, which can insulate the surface of the conductive connecting piece exposed between the first end plate and the second end plate, so that the creepage path between the conductive connecting piece and the first end plate and the second end plate needs to pass through the insulating layer to the side plate of the output pole base, and then to the exposed first end plate and the second end plate, thereby increasing the creepage distance between the original energized conductive connecting piece and the exposed surfaces of the first end plate and the second end plate, thereby improving the creepage short circuit phenomenon between the conductive connecting piece and the first end plate and the second end plate, improving the safety performance of the battery pack, and further improving the safety of the energy storage system.

[0045] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification are used to explain the principles of the present disclosure. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0047] Figure 1 A schematic diagram of an energy storage system provided for one embodiment of the present disclosure.

[0048] Figure 2 A schematic diagram of a battery pack provided for an embodiment of the present disclosure.

[0049] Figure 3 An exploded schematic diagram of a battery pack provided for an embodiment of the present disclosure.

[0050] Figure 4 A schematic diagram of a battery module provided for one embodiment of the present disclosure.

[0051] Figure 5 A schematic diagram of electrical connection between a first battery module and a second battery module provided in accordance with an embodiment of the present disclosure.

[0052] Figure 6 for Figure 5 A partial enlarged view of point A in the middle.

[0053] Figure 7 A schematic diagram of removing a base cover after the electrical connection between a first battery module and a second battery module provided in an embodiment of the present disclosure.

[0054] Figure 8 for Figure 7 A partial enlarged view of point B in the middle.

[0055] Fig. 9 A schematic diagram from another perspective of removing the base cover after the electrical connection between the first battery module and the second battery module provided in an embodiment of the present disclosure.

[0056] Fig.10 for Fig. 9 A partial enlarged view of point C in the middle.

[0057] Fig.11 A schematic diagram of an electrical connection structure between a first battery module and a second battery module provided in accordance with an embodiment of the present disclosure.

[0058] Fig.12 A schematic diagram of a conductive connecting piece provided in an embodiment of the present disclosure.

[0059] Fig.13 A schematic diagram of a first transition connecting piece and a second transition connecting piece provided for an embodiment of the present disclosure.

[0060] Fig.14 A schematic diagram of a first transition connecting piece and a second transition connecting piece provided for another embodiment of the present disclosure.

[0061] Fig.15 A schematic diagram of a first output pole base and a second output pole base provided for an embodiment of the present disclosure.

[0062] Fig.16 A schematic diagram of a first output pole base and a second output pole base from another perspective provided in an embodiment of the present disclosure.

[0063] Description of reference numerals:

[0064] 10. Energy storage device; 20. Power grid; 30. First power conversion device; 40. Second power conversion device;

[0065] 100. Battery pack;

[0066] 110, battery box; 111, lower box; 112, box cover;

[0067] 120. Battery module;

[0068] 121, first battery module; 1211, first battery cell; 1212, first end plate; 1213, first output pole base; 12131, first base; 12132, first protrusion; 12133, first side plate; 12134, first extension; 12135, first extension; 12136, first reinforcing rib; 1214, first base cover; 1215, first output pole connecting plate; 1216, first battery cell connecting plate; 1217, first cable tie; 1218, first insulating plate;

[0069] 122, second battery module; 1221, second battery cell; 1222, second end plate; 1223, second output pole base; 12231, second base; 12232, second protrusion; 12233, second side plate; 12234, second extension; 12235, second extension; 12236, second reinforcing rib; 1224, second base cover; 1225, second output pole connecting piece; 1226, second battery cell connecting piece; 1227, second tie; 1228, second insulating plate;

[0070] 123, first transition connecting piece; 1231, first end; 1232, second end; 1233, third connecting portion; 1234, fourth connecting portion; 1235, first bending portion; 1236, first avoidance gap; 1237, first conductive layer; 1238, second conductive layer; 1239, second via hole;

[0071] 124, second transition connecting piece; 1241, first end; 1242, second end; 1243, fifth connecting portion; 1244, sixth connecting portion; 1245, second bending portion; 1246, second avoidance gap; 1247, third conductive layer; 1248, fourth conductive layer; 1249, fourth via hole;

[0072] 125, conductive connecting piece; 1251, first end; 1252, second end; 1253, first connecting portion; 1254, second connecting portion; 1255, middle connecting portion; 1256, insulating layer; 1257, first via hole; 1258, third via hole;

[0073] 1261, a first threaded member; 1262, a second threaded member; 1263, a third threaded member; 1264, a fourth threaded member. DETAILED DESCRIPTION

[0074] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be comprehensive and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their detailed description will be omitted.

[0075] Since the energy people need is highly temporal and spatial, in order to rationally utilize energy and improve utilization, it is necessary to use a medium or device to store one form of energy in the same energy form, or convert it into another form of energy, and then release it in a specific energy form based on future applications.

[0076] At present, green energy mainly includes solar energy, wind energy, etc., which generally have problems of strong intermittency and large volatility, which will cause unstable voltage of the green power grid (not enough electricity during peak hours and too much electricity during low hours). Unstable voltage will cause damage to electricity. Therefore, it may cause the problem of "wind and solar power abandonment" due to insufficient electricity demand or insufficient grid acceptance capacity.

[0077] To solve the problem of insufficient electricity demand or insufficient grid acceptance capacity, we must rely on energy storage devices. That is, the energy storage device converts electrical energy into other forms of energy through physical or chemical means and stores it, and then converts the energy stored in the energy storage device into electrical energy when needed. In simple terms, the energy storage device is similar to a large "power bank", which stores electrical energy when there is sufficient light energy and wind energy, and releases the stored electrical energy when needed.

[0078] At present, energy storage (i.e. energy storage) has a wide range of application scenarios, including power generation side energy storage, grid side energy storage, renewable energy grid-connected energy storage and user side energy storage. The corresponding types of energy storage devices include:

[0079] (1) Large-scale energy storage power stations used in energy storage scenarios on the power generation side, such as wind power and photovoltaic power stations, can assist renewable energy generation in meeting grid connection requirements while improving the utilization rate of renewable energy. As a high-quality active / reactive power source on the power supply side, energy storage power stations can achieve load matching of electricity in time and space, enhance the ability to absorb renewable energy, reduce instantaneous power changes, reduce the impact on the power grid, improve the problem of new energy generation and absorption, and are of great significance in power grid system backup, relieving peak load power supply pressure, and peak and frequency regulation.

[0080] (2) Large energy storage containers used in grid-side energy storage scenarios mainly perform peak load regulation, frequency regulation, and grid congestion relief. Peak load regulation can achieve peak load shaving and valley filling, that is, charging the energy storage battery when the load is low and releasing the stored electricity during the peak load period, thereby achieving a balance between power production and consumption, such as energy storage power station systems;

[0081] (3) Small and medium-sized energy storage cabinets used in industrial and commercial energy storage scenarios (banks, shopping malls, etc.) on the user side and small household energy storage boxes used in household energy storage scenarios on the user side. Their main functions are self-generation and self-use of electricity, peak shaving and valley filling, capacity cost management, and improved power supply reliability. According to different application scenarios, energy storage on the power consumption side can be divided into industrial and commercial energy storage cabinets, household energy storage devices, energy storage charging piles, etc., which are generally used in conjunction with distributed photovoltaics. Since there is a large price difference in electricity prices at peak and valley locations according to electricity demand, after users have energy storage devices, in order to reduce costs, they usually charge the energy storage devices (energy storage cabinets / boxes) during the low electricity price period; during the peak electricity price period, the electricity in the energy storage devices is discharged for use to achieve the purpose of saving electricity costs. In addition, communication base stations, data centers and other fields need to be equipped with energy storage for backup power supply. In addition, in remote areas and areas prone to natural disasters such as earthquakes and hurricanes, the existence of household energy storage devices is equivalent to users providing backup power for themselves and the power grid, eliminating the inconvenience caused by frequent power outages due to disasters or other reasons.

[0082] Figure 1 A schematic diagram of an energy storage system provided in accordance with an embodiment of the present disclosure, and the present disclosure Figure 1 The embodiment is described by taking the shared energy storage scenario on the power generation / distribution side as an example. The energy storage system disclosed in the present invention is not limited to the energy storage scenario on the power generation / distribution side, but can also be applied to scenarios on the industrial and commercial side or the user side.

[0083] like Figure 1 As shown, the energy storage system includes: an energy storage device 10, a power grid 20, a first power conversion device 30, and a second power conversion device 40. In the case of power generation, the first power conversion device 30 and the second power conversion device 40 are used to convert other forms of energy into electric energy, connect to the power grid 20, and supply the power distribution network to the power consumption side; when the power load is low and the first power conversion device 30 and the second power conversion device 40 generate excess power, the excess power is stored in the energy storage device 10, reducing the wind and light abandonment rate and improving the problem of new energy power generation and consumption; when the power load is high, the power grid issues an instruction to use the power stored in the energy storage device 10 to coordinate with the power grid 20 to adopt the grid-connected mode to transmit the power to the power consumption side, providing peak shaving, frequency regulation, standby and other services for the operation of the power grid 20, giving full play to the peak shaving role of the power grid 20, promoting the peak shaving and valley filling of the power grid 20, and alleviating the power supply pressure of the power grid 20.

[0084] Among them, the first power conversion device 30 can be a solar energy conversion device, and the second power conversion device 40 can be a wind energy conversion device; of course, the power conversion device can also be a device that converts at least one of thermal energy, tidal energy, biomass energy and mechanical energy into electrical energy.

[0085] In combination with the above-mentioned situation of storing energy by physical or electrochemical means, taking electrochemical energy storage as an example, the energy storage device 10 includes at least one chemical battery, using the chemical elements in the chemical battery as the energy storage medium, so as to realize the charging and discharging process through the chemical reaction or change of the energy storage medium. In simple terms, the electric energy generated by light energy and wind energy is stored in at least one group of chemical batteries through the chemical reaction or change of the energy storage medium, and when the use of external electric energy reaches a peak, the electric energy stored in at least one group of chemical batteries is released for use through the chemical reaction or change of the energy storage medium, or transferred to a place where electric energy is scarce for use.

[0086] The energy storage device 10 may be a battery pack, an energy storage box, an energy storage cabinet, etc., which are composed of battery cells. The battery cells may be lithium-ion secondary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, magnesium-ion batteries, etc., and the battery cells may be cylindrical, flat, rectangular, etc., which are not limited in the embodiments of the present application.

[0087] like Figure 2~Figure 4 As shown, taking the energy storage device 10 as an example of a battery pack 100, the battery pack 100 includes a battery case 110 and a plurality of battery modules 120, the battery case 110 includes a lower case 111 and a case cover 112, and the case cover 112 is fixedly / detachably connected to the lower case 111 to form a battery compartment; the plurality of battery modules 120 are located in the battery compartment.

[0088] The battery module 120 contained in the battery compartment of the battery box 110 may be at least one, such as one, two, four, five, six, seven, eight or more, and the more the number of battery modules 120 is, the higher the capacity of the battery pack 100 is, so that it is easier to meet the market demand. Figure 3 As shown, the battery compartment of the battery box 110 accommodates eight battery modules 120 in two rows along the length direction of the battery box 110 and four columns along the width direction of the battery box 110 .

[0089] Each battery module 120 may include a pair of end plates arranged opposite to each other along the direction of battery cell grouping, and a plurality of battery cells located between the pair of end plates. The plurality of battery cells and the pair of end plates may be fixed by a binding tool such as a cable tie, and the plurality of battery cells are arranged along the length direction of the battery case 110, and the plurality of battery cells are connected by a battery cell connecting sheet to realize series / parallel electrical connection between the plurality of battery cells. For example, Figure 5As shown, the first battery module 121 includes a pair of first end plates 1212 arranged opposite to each other, and a plurality of first battery cells 1211 located between the pair of first end plates 1212. The plurality of first battery cells 1211 and the pair of first end plates 1212 are bundled and fixed by a first cable tie 1217. The plurality of first battery cells 1211 are arranged along the length direction of the battery case 110, and the plurality of first battery cells 1211 are connected by a first battery cell connecting sheet 1216 to realize series / parallel electrical connection between the plurality of first battery cells 1211. The second battery module 122 includes a pair of second end plates 1222 arranged opposite to each other, and a plurality of second battery cells 1221 located between the pair of second end plates 1222. The plurality of second battery cells 1221 and the pair of second end plates 1222 are bundled and fixed by a second cable tie 1227. The plurality of second battery cells 1221 are arranged along the length direction of the battery case 110, and the plurality of second battery cells 1221 are connected by a second battery cell connecting sheet 1226 to realize series / parallel electrical connection between the plurality of second battery cells 1221.

[0090] Among them, multiple battery cells are connected in series in sequence, and each battery cell connecting piece is respectively connected to electrode terminals of different polarities on two battery cells; or, multiple battery cells are connected in parallel in groups of two and then connected in series between groups, and each battery cell connecting piece is firstly connected to electrode terminals of the same polarity on two battery cells, and then connected to electrode terminals of opposite polarity on the other two battery cells.

[0091] Among them, the outer wall of each battery cell can be covered with an insulating film to avoid the safety hazard caused by the battery cell shell leakage; since the end plate is usually made of aluminum and has a certain strength structure, such as Figure 5 and Figure 6 As shown, the first battery module 121 includes a first insulating plate 1218 located between the first end plate 1212 and the adjacent first battery cell 1211, so as to prevent burrs or protruding structures on the first end plate 1212 from piercing the insulating film on the first battery cell 1211, and to prevent the first end plate 1212 from being charged due to leakage of the first battery cell 1211; at the same time, since the first battery cell 1211 is charged and the first end plate 1212 is not charged, by setting the first insulating plate 1218, the creepage distance between the first battery cell 1211 and the first end plate 1212 can be increased, thereby ensuring that the first end plate 1212 is not charged, thereby preventing the battery box 110 from being charged, and improving the safety of the staff's operation.

[0092] Among them, the second battery module 122 includes a second insulating plate 1228 located between the second end plate 1222 and the adjacent second battery cell 1221, so as to prevent burrs or protruding structures on the second end plate 1222 from piercing the insulating film on the second battery cell 1221, and at the same time prevent the second end plate 1222 from being charged due to leakage of the second battery cell 1221; at the same time, since the second battery cell 1221 is charged and the second end plate 1222 is not charged, by setting the second insulating plate 1228, the creepage distance between the second battery cell 1221 and the second end plate 1222 can be increased, ensuring that the second end plate 1222 is not charged, thereby preventing the battery box 110 from being charged, thereby improving the safety of the staff's operation.

[0093] In the related art, since the copper busbar between the battery modules 120 spans the end plates of the two battery modules 120 and the two ends are respectively located on the output pole bases on the end plates, a part of the copper busbar is suspended between the two end plates; at this time, the distance between the charged copper busbar located in the middle suspension and the end plates at both ends is too close, and a creepage short circuit may occur. When there are pollutants such as suspended dust or charged particles in the air around the output pole base, the creepage distance between the copper busbar and the end plate will be further reduced, resulting in creepage between the two, and eventually causing the end plate to be charged, posing a serious threat to the safety of the battery pack 100.

[0094] In view of the above technical problems, the embodiments of the present disclosure provide a battery pack 100, such as Figure 2 to Figure 12 As shown, the battery pack 100 includes: a battery case 110, a plurality of battery modules 120 and a conductive connecting piece 125. The battery case 110 is formed with a battery compartment, and the plurality of battery modules 120 are located in the battery compartment; each battery module 120 includes a plurality of battery cells arranged along a first direction X and end plates clamped at both ends of the plurality of battery cells, and the first direction X may be the length direction of the battery pack 100; the plurality of battery modules 120 at least include a first battery module 121 and a second battery module 122 arranged adjacent to each other along the first direction X; below, the present disclosure takes the first battery module 121 and the second battery module 122 as an example to discuss in detail the electrical connection structure between adjacent battery modules 120.

[0095] Among them, an insulating first output pole base 1213 is provided on the first end plate 1212 adjacent to the second battery module 122 in the first battery module 121, and a first output pole connecting plate 1215 is provided on the battery cell adjacent to the first end plate 1212; an insulating second output pole base 1223 is provided on the second end plate 1222 adjacent to the first battery module 121 in the second battery module 122, and a second output pole connecting plate 1225 is provided on the battery cell adjacent to the second end plate 1222.

[0096] Among them, the conductive connecting piece 125 includes a first connecting part 1253, a second connecting part 1254 and an intermediate connecting part 1255 located between the first connecting part 1253 and the second connecting part 1254, which are arranged relatively along the first direction X. The first connecting part 1253 is connected to the first output pole connecting piece 1215, and the second connecting part 1254 is connected to the second output pole connecting piece 1225; in the first direction X, the intermediate connecting part 1255 has an overlapping part with the first output pole base 1213 and the second output pole base 1223; an insulating layer 1256 is provided on the surface of the intermediate connecting part 1255, and the insulating layer 1256 has an overlapping part with the first output pole base 1213 and the second output pole base 1223.

[0097] In the battery pack 100 provided by the present disclosure, the two ends of the conductive connecting piece 125 are respectively located on the first output pole base 1213 and the second output pole base 1223, thereby achieving insulation between the first end plate 1212 and the second end plate 1222; at the same time, the intermediate connecting portion 1255 on the conductive connecting piece 125 is located between the first end plate 1212 and the second end plate 1222, and an insulating layer 1256 is provided on the surface of the intermediate connecting portion 1255, which can insulate the surface of the conductive connecting piece 125 exposed between the first end plate 1212 and the second end plate 1222; since the distance between the suspended charged conductive connecting piece 125 and the first end plate 1212 and the second end plate 1222 at both ends is too close, creepage may occur on the shortest path between the charged conductive connecting piece 125 and the first end plate 1212 and the second end plate 1222 at both ends when the conductive connecting piece 125 is exposed; when the conductive The connecting piece 125 is not provided with an insulating layer 1256, and the creepage distance is the shortest path from the middle connecting portion 1255 of the conductive connecting piece 125 across the bottom height of the first output pole connecting piece 1215 and the second output pole base 1223 to the surface of the first end plate 1212 and the second end plate 1222; when the conductive connecting piece 125 is provided with an insulating layer 1256, the creepage path between the conductive connecting piece 125 and the first end plate 1212 and the second end plate 1222 needs to pass through the insulating layer 1256 and then reach the exposed first end plate 1212 and the second end plate 1222, thereby increasing the creepage distance between the energized conductive connecting piece 125 and the exposed surfaces of the first end plate 1212 and the second end plate 1222, thereby improving the creepage short circuit phenomenon between the conductive connecting piece 125 and the first end plate 1212 and the second end plate 1222, and improving the safety performance of the battery pack 100.

[0098] In addition, under normal working conditions of the battery cell, the expansion of the battery cell will cause the entire battery module 120 to be displaced due to expansion. In this case, the distance between the first battery module 121 and the second battery module 122 will change due to the displacement. At this time, the conductive connecting piece 125 will be stretched, causing the conductive connecting piece 125 originally covered under the insulating layer 1256 to be exposed due to stretching. The exposed area of ​​the conductive connecting piece 125 becomes larger and is exposed from the gap between the first end plate 1212 and the second end plate 1222, resulting in the conductive connecting piece 125 and the first end plate 1212 being exposed. The creepage distance between the exposed surfaces of the plate 1212 and the second end plate 1222 is reduced, which may easily lead to a creepage short circuit phenomenon; therefore, the edge position of the insulating layer 1256 is moved inward to the inner side of the first output pole base 1213 and the second output pole base 1223. In the event that the first battery module 121 and the second battery module 122 expand and displace and stretch the conductive connecting piece 125, the creepage distance between the conductive connecting piece 125 and the first end plate 1212 and the second end plate 1222 is guaranteed to be within the insulation safety range to the greatest extent, thereby avoiding safety accidents caused by short circuits.

[0099] In one embodiment, the insulating layer 1256 is made of elastic material. By using the insulating layer 1256 made of elastic material, when the conductive connecting piece 125 is a non-planar structure, such as a bent structure, the insulating layer 1256 made of elastic material can better fit the surface of the conductive connecting piece 125 to improve the insulation performance of the conductive connecting piece 125.

[0100] The insulating layer 1256 is bonded to the conductive connecting piece 125. The insulating layer 1256 is fixedly connected to the conductive connecting piece 125 by bonding, which is convenient for setting the insulating layer 1256 on the conductive connecting piece 125; at the same time, it is convenient to bond and cover the part of the conductive connecting piece 125 that needs to be insulated according to actual needs. In addition, when the insulating layer 1256 is damaged and fails, it is convenient to tear off and replace the insulating layer 1256.

[0101] The insulating layer 1256 is an insulating tape. The insulating tape is used to facilitate the arrangement of the insulating layer 1256 on the conductive connecting piece 125. The insulating tape has good elasticity and can be tightly attached to the surface of the conductive connecting piece 125 by bonding. The insulating tape can be wrapped around the portion of the conductive connecting piece 125 that needs to be insulated for multiple turns to improve the insulation effect and prevent the insulating layer 1256 from being easily pierced when the thickness is relatively thin.

[0102] Of course, the insulating layer 1256 can also be formed by spraying or injection molding, and the present disclosure does not limit this. Any insulating layer 1256 that can achieve an insulating effect and any method of setting the insulating layer 1256 are within the protection scope of the present disclosure.

[0103] In one embodiment, an insulating layer 1256 is disposed on the surface of the intermediate connecting portion 1255. The insulating layer 1256 may be disposed on the suspended portion of the conductive connecting piece 125 and the portion overlapping the first output pole connecting piece 1215 and the second output pole base 1223, or the portion of the conductive connecting piece 125 that is not in contact with other conductive members, so as to further improve the insulation of the exposed portion of the conductive connecting piece 125, thereby further improving the creepage short circuit phenomenon between the conductive connecting piece 125 and the first end plate 1212 and the second end plate 1222, and further improving the safety performance of the battery pack 100.

[0104] Specifically, Fig.12 As shown, there is a preset gap between the first battery module 121 and the second battery module 122 along the first direction X, and the intermediate connection portion 1255 is arranged corresponding to the preset gap. By arranging an insulating layer 1256 on the intermediate connection portion 1255, the surface of the conductive connection sheet 125 exposed in the preset gap can be insulated.

[0105] Among them, at least part of the middle connection part 1255 is in a bending structure, and the bending structure can make the first connection part 1253 and the second connection part 1254 move away from or towards each other along the first direction X. Since the battery cells of the battery cells expand after long-term use, the conductive connecting piece 125 will be subjected to the tensile force from the first battery module 121 and the second battery module 122, which will cause the conductive connecting piece 125 to have a tensile force in the second direction Z, which may easily cause the conductive connecting piece 125 to deform or even break; by setting the bending structure, when the conductive connecting piece 125 is subjected to the tensile force, the tensile force can be absorbed by the bending structure, thereby avoiding the conductive connecting piece 125 from breaking. Of course, the conductive connecting piece 125 may not be provided with a bending structure, and the present disclosure does not limit this.

[0106] When the intermediate connection portion 1255 is provided with a bending structure, it is required that when the conductive connection piece 125 is in the maximum stretched state, the portion of the conductive connection piece 125 located between the first end plate 1212 and the second end plate 1222 can also be covered by the insulating layer 1256 .

[0107] Among them, the insulating layer 1256 is made of elastic material. When the first connecting portion 1253 and the second connecting portion 1254 move away from or towards each other along the first direction X, the insulating layer 1256 made of elastic material can stretch or shrink to avoid stretching the conductive connecting piece 125 when the first connecting portion 1253 and the second connecting portion 1254 move away from each other along the first direction X, so that the part originally covered under the insulating layer 1256 is exposed due to the stretching, thereby improving the insulation effect of the conductive connecting piece 125. At the same time, by providing an insulating layer 1256 made of elastic material, when the first battery module 121 and the second battery module 122 expand and displace and stretch the conductive connecting piece 125, it is possible to ensure to the greatest extent that there is an overlapping portion between the insulating layer 1256 and the first output pole connecting piece 1215 and the second output pole base 1223, that is, to ensure that the creepage distance between the conductive connecting piece 125 and the first end plate 1212 and the second end plate 1222 is within the insulation safety range, thereby avoiding safety accidents caused by short circuits.

[0108] Among them, the insulating layer 1256 can be set to have a sufficient overlapping length between the first output pole connecting piece 1215 and the second output pole base 1223 in the first direction X, so that the first connecting part 1253 and the second connecting part 1254 move away from each other along the first direction X, so that when the middle connecting part 1255 with a bent structure is in a straight state, the insulating layer 1256 has an overlapping part with the first output pole connecting piece 1215 and the second output pole base 1223 in the first direction X, thereby ensuring that the creepage distance between the conductive connecting piece 125 and the first end plate 1212 and the second end plate 1222 is within the insulation safety range, thereby avoiding safety accidents caused by short circuits.

[0109] Of course, when the middle connecting portion 1255 is not provided with a bending structure, the above-mentioned method of using an insulating layer 1256 of elastic material and setting an insulating layer 1256 of sufficient length can also be adopted to meet the requirement that when the conductive connecting piece 125 is in the maximum stretched state, the part of the conductive connecting piece 125 located between the first end plate 1212 and the second end plate 1222 can also be covered by the insulating layer 1256.

[0110] In one embodiment, Figure 7 , Figure 8 and Fig.15As shown, the first output pole base 1213 is arranged on one side of the first end plate 1212 along the second direction Z, and the first output pole base 1213 is provided with first side plates 12133 extending toward the second direction Z on both sides along the third direction Y; in the second direction Z, the height of the first side plate 12133 is greater than the thickness of the first connecting portion 1253. Since the first base 12131 of the first output pole base 1213 is separated between the live conductive connection piece 125 and the surface of the first end plate 1212 directly below it, the dielectric constant of the first base 12131 is relatively large and no creepage phenomenon occurs; therefore, the creepage between the live conductive connection piece 125 and the first end plate 1212 passes through the first side plate 12133 of the first output pole base 1213, and the specific creepage occurs between the live conductive connection piece 125 and the exposed surface of the first end plate 1212 that is closest to it, and the creepage occurs between the live conductive connection piece 125 and the exposed surface of the first end plate 1212 that is closest to it. By increasing the height of the first side plate 12133, the creepage distance between the conductive connecting piece 125 in the first output pole base 1213 and the first end plate 1212 directly below it can be increased, thereby preventing the battery pack 100 from being in use. When there are pollutants such as suspended dust or charged particles in the air around the first output pole base 1213, the creepage distance between the conductive connecting piece 125 and the first end plate 1212 will be reduced, resulting in creepage between the two, and further causing a safety accident in which the first end plate 1212 is charged.

[0111] Among them, Fig. 9 , Fig.10 and Fig.15 As shown, the second output pole base 1223 is arranged on one side of the second end plate 1222 along the second direction Z, and the second side plates 12233 extending toward the second direction Z are respectively arranged on both sides of the second output pole base 1223 along the third direction Y; in the second direction Z, the height of the second side plate 12233 is greater than the thickness of the second connecting portion 1254. By increasing the height of the second side plate 12233, the creepage distance between the conductive connecting piece 125 in the second output pole base 1223 and the second end plate 1222 directly below it can be increased, so as to prevent the battery pack 100 from being used. When there are pollutants such as suspended dust or charged particles in the air around the second output pole base 1223, the creepage distance between the conductive connecting piece 125 and the second end plate 1222 is reduced, resulting in creepage between the two, thereby avoiding a safety accident in which the second end plate 1222 is charged.

[0112] In one embodiment, Figure 7 , Figure 8 and Fig.15As shown, when a first side plate 12133 is provided on the first output pole base 1213, a first extension portion 12134 extending along the first direction X toward one side of the second end plate 1222 is provided on the first side plate 12133, and the first extension portion 12134 protrudes from the first end plate 1212 in the first direction X. Since the conductive connecting piece 125 between the first battery module 121 and the second battery module 122 spans the first end plate 1212 and the second end plate 1222, and the two ends are respectively located on the first output pole base 1213 and the second output pole base 1223, a part of the conductive connecting piece 125 is suspended between the first end plate 1212 and the second end plate 1222; at this time, the distance between the conductive connecting piece 125 located in the middle suspended position and the end plates at both ends is too close, and a creepage short circuit may occur. The creepage current between the exposed charged conductive connecting piece 125 and the first end plate 1212 and the second end plate 1222 passes through the first side plate 12133 and the second side plate 12233. The first extension portion 12134 on the first side plate 12133 extends to the outside of the first end plate 1212, thereby increasing the distance between the live conductive connecting piece 125 and the first end plate 1212, so that the battery cell can better ensure the insulation between the first end plate 1212 and the live conductive connecting piece 125 both in working and non-working conditions, thereby preventing a short circuit between the two.

[0113] Among them, Fig. 9 , Fig.10 and Fig.15 As shown, when the second output pole base 1223 is provided with a second side plate 12233, the second side plate 12233 is provided with a second extension portion 12234 extending along the second direction Z toward one side of the first end plate 1212, and the second extension portion 12234 protrudes from the second end plate 1222 in the first direction X. The second extension portion 12234 on the second side plate 12233 extends to the outside of the second end plate 1222, thereby increasing the distance between the live conductive connection sheet 125 and the second end plate 1222, so that the battery cell can better ensure the insulation between the first end plate 1212 and the live conductive connection sheet 125 in both working and non-working conditions, thereby preventing the occurrence of a short circuit between the two.

[0114] In one embodiment, Figure 7 , Figure 8 and Fig.15As shown, the first output pole base 1213 includes a first base 12131 located between the first connecting portion 1253 and the first end plate 1212, and the first base 12131 is provided with a first protrusion 12132 extending along the first direction X toward one side of the second end plate 1222, and the first protrusion 12132 protrudes from the first end plate 1212 in the first direction X. By setting the first protrusion 12132 on the first base 12131, the first protrusion 12132 protrudes to the top of the outer side of the first end plate 1212, so that the creepage path between the live conductive connecting piece 125 and the exposed first end plate 1212 is the live conductive connecting piece 125-insulating layer 1256-first protrusion 12132-first end plate 1212, thereby increasing the distance between the conductive connecting piece 125 and the exposed first end plate 1212, so that the insulation between the first end plate 1212 and the live conductive connecting piece 125 can be better ensured in both working and non-working conditions of the battery cell, thereby preventing the occurrence of a short circuit between the two.

[0115] Among them, Fig. 9 , Fig.10 and Fig.15 As shown, the second output pole base 1223 includes a second base 12231 located between the second connecting portion 1254 and the second end plate 1222, and the second base 12231 is provided with a second protrusion 12232 extending along the first direction X toward one side of the first end plate 1212, and the second protrusion 12232 protrudes from the second end plate 1222 in the first direction X. By arranging a second protrusion 12232 on the second base 12231, the second protrusion 12232 protrudes to the top outer side of the second end plate 1222, so that the creepage path between the live conductive connecting piece 125 and the exposed second end plate 1222 is live conductive connecting piece 125-insulating layer 1256-second protrusion 12232-second end plate 1222, thereby increasing the distance between the conductive connecting piece 125 and the exposed second end plate 1222, so that the insulation between the second end plate 1222 and the live conductive connecting piece 125 can be better ensured in both working and non-working conditions, thereby preventing a short circuit between the two.

[0116] Among them, Fig.15As shown, the first extension portion 12134 on the first side plate 12133 of the first output pole base 1213, the first extension portion 12134 and the first protrusion 12132 on the first base 12131 can be arranged flush with each other on the outer edge of the first end plate 1212 to enhance the structural strength of the first extension portion 12134 and the outer edge of the first protrusion 12132; the second extension portion 12234 on the second side plate 12233 of the second output pole base 1223, the second extension portion 12234 and the second protrusion 12232 on the second base 12231 can be arranged flush with each other on the outer edge of the second end plate 1222 to enhance the structural strength of the second extension portion 12234 and the outer edge of the second protrusion 12232.

[0117] In one embodiment, Figure 7 , Figure 8 and Fig.15 As shown, the first output pole base 1213 is arranged on one side of the first end plate 1212 along the second direction Z, and the first output pole base 1213 is provided with a first extension portion 12135 extending toward one side of the first end plate 1212, and the first extension portion 12135 and the first end plate 1212 have an overlapping portion in the second direction Z. The distance between the conductive connecting piece 125 located in the middle suspension and the end plates at both ends is too close, and a creepage short circuit may occur. The creepage between the exposed live conductive connecting piece 125 and the first end plate 1212 and the second end plate 1222 passes through the first side plate 12133 and the second side plate 12233. The first extension portion 12135 shields the portion of the conductive connection piece 125 directly below and closest to the first end plate 1212, thereby increasing the distance between the live conductive connection piece 125 and the first end plate 1212. This allows the battery cell to better ensure insulation between the first end plate 1212 and the live conductive connection piece 125 both in operating and non-operating conditions, thereby preventing a short circuit between the two.

[0118] Among them, Fig. 9 , Fig.10 and Fig.15 As shown, the second output pole base 1223 is arranged at one side of the second end plate 1222 along the second direction Z, and the second output pole base 1223 is provided with a second extension portion 12235 extending toward one side of the second end plate 1222, and the second extension portion 12235 and the second end plate 1222 have an overlapping portion in the second direction Z. The second extension portion 12235 shields the portion directly below the conductive connection sheet 125 and closest to the second end plate 1222, that is, the distance between the charged conductive connection sheet 125 and the second end plate 1222 is increased, so that the insulation between the second end plate 1222 and the charged conductive connection sheet 125 can be better ensured in both the working condition and the non-working condition of the battery cell, thereby preventing the occurrence of a short circuit between the two.

[0119] Among them, Fig.16 As shown, a first reinforcing rib 12136 is provided between the first protruding portion 12132 on the first base 12131 and the first extension portion 12135. Since the first extension portion 12135 extends toward one side of the first end plate 1212 in a plate shape, the first reinforcing rib 12136 is provided to improve the structural strength of the first extension portion 12135, thereby preventing the first extension portion 12135 from being deformed or broken after being subjected to force.

[0120] Among them, Fig.16 As shown, a second reinforcing rib 12236 is provided between the second protruding portion 12232 on the second base 12231 and the second extension portion 12235. Since the second extension portion 12235 extends toward the second end plate 1222 in a plate shape, the second reinforcing rib 12236 is provided to improve the structural strength of the second extension portion 12235, thereby preventing the second extension portion 12235 from being deformed or broken after being subjected to force.

[0121] In one embodiment, Figure 5~Figure 13 As shown, the battery pack 100 also includes: a first transition connecting piece 123 and a second transition connecting piece 124, the first transition connecting piece 123 is located on the first output pole base 1213 and is connected to the first output pole connecting piece 1215, and the resistance of the first transition connecting piece 123 is less than the resistance of the first output pole connecting piece 1215; the second transition connecting piece 124 is located on the second output pole base 1223 and is connected to the second output pole connecting piece 1225, and the resistance of the second transition connecting piece 124 is less than the resistance of the second output pole connecting piece 1225; the conductive connecting piece 125 includes a first end 1251 and a second end 1252 that are relatively arranged, the first end 1251 is connected to the first transition connecting piece 123, and the second end 1252 is connected to the second transition connecting piece 124.

[0122] In the battery pack 100 provided in this embodiment, a first transition connecting piece 123 is provided on the first output pole base 1213, a second transition connecting piece 124 is provided on the second output pole base 1223, a first end 1251 of the conducting connecting piece 125 is connected and conducted with the first output pole connecting piece 1215 through the first transition connecting piece 123, and a second end 1252 of the conducting connecting piece 125 is connected and conducted with the second output pole connecting piece 1225 through the second transition connecting piece 124; since the resistance of the first transition connecting piece 123 is less than that of the first output pole connecting piece 1 215, the resistance of the second transition connecting piece 124 is less than the resistance of the second output pole connecting piece 1225, thereby improving the overcurrent capacity of the corresponding electrical connectors on the first output pole base 1213 and the second output pole base 1223, avoiding the problem that the overcurrent capacity is relatively low after the first output pole connecting piece 1215 is located on the first output pole base 1213 and the second output pole connecting piece 1225 is located on the second output pole base 1223, which causes the output pole connecting piece to easily heat up seriously, fuse, and cause electrical connection failure.

[0123] Among them, when the first transition connecting piece 123 is set on the first output pole base 1213, the first end 1251 of the conductive connecting piece 125 can be located on the first transition connecting piece 123; at this time, the height of the first side plate 12133 is greater than the sum of the thicknesses of the first transition connecting piece 123 and the conductive connecting piece 125.

[0124] Among them, when the second transition connecting piece 124 is set on the second output pole base 1223, the second end 1252 of the conductive connecting piece 125 can be located on the second transition connecting piece 124; at this time, the height of the second side plate 12233 is greater than the sum of the thicknesses of the second transition connecting piece 124 and the conductive connecting piece 125.

[0125] Specifically, a first limiting groove is provided on the first output pole base 1213, and the first transition connecting piece 123 is located in the first limiting groove; along the third direction Y, the width of at least part of the first output pole connecting piece 1215 is greater than the width of the first limiting groove, that is, the width of the first output pole base 1213 is smaller than the width of the first output pole connecting piece 1215. When the first output pole connecting piece 1215 needs to be placed on the first output pole base 1213, the first output pole connecting piece 1215 needs to be set to a shape with different widths, that is, the width of one end of the first output pole connecting piece 1215 close to the first output pole base 1213 is narrowed so as to be placed on the first output pole base 1213; by setting the first transition connecting piece 123, it replaces the first output pole connecting piece 1215 and is located on the first output pole base 1213 and connected to the conductive connecting piece 125.

[0126] Among them, a second limiting groove is provided on the second output pole base 1223, and the second transition connecting piece 124 is located in the second limiting groove; along the third direction Y, the width of at least part of the second output pole connecting piece 1225 is greater than the width of the second limiting groove, that is, the width of the second output pole base 1223 is smaller than the width of the second output pole connecting piece 1225. When the second output pole connecting piece 1225 needs to be placed on the second output pole base 1223, the second output pole connecting piece 1225 needs to be set to a shape with different widths, that is, the width of one end of the second output pole connecting piece 1225 close to the second output pole base 1223 is narrowed so as to be placed on the second output pole base 1223; by setting the second transition connecting piece 124, it replaces the second output pole connecting piece 1225 and is located on the second output pole base 1223 and is connected to the conductive connecting piece 125.

[0127] Specifically, the first output pole connecting piece 1215 and the first output pole base 1213 are spaced apart in the first direction X, and the first transition connecting piece 123 includes a first end 1231 and a second end 1232 that are oppositely arranged, and the first end 1231 of the first transition connecting piece 123 extends out of the first output pole base 1213 and is connected to the first output pole connecting piece 1215.

[0128] Among them, when the first limiting groove formed by the first output pole base 1213 is an equal width structure, by making the first end 1231 of the first transition connecting piece 123 extend out of the first output pole base 1213 and connect with the first output pole connecting piece 1215, it is possible to avoid the first output pole connecting piece 1215 from narrowing at one end close to the first output pole base 1213, so that the first output pole connecting piece 1215 has a sufficient width, thereby ensuring the overcurrent capacity of the first output pole connecting piece 1215 and avoiding the situation of heating or even melting. When the first limiting groove formed by the first output pole base 1213 is a non-wide structure, for example, when the width of one end close to the first output pole connecting piece 1215 is relatively large, the first output pole connecting piece 1215 can also be partially located on the first output pole base 1213 with a larger width and connected with the first transition connecting piece 123. At this time, the first end 1231 of the first transition connecting piece 123 does not need to extend out of the first output pole base 1213, and the width of the first output pole connecting piece 1215 is not affected, and its overcurrent capacity is reduced.

[0129] Specifically, the second output pole connecting piece 1225 and the second output pole base 1223 are spaced apart in the first direction X, and the second transition connecting piece 124 includes a first end 1241 and a second end 1242 that are oppositely arranged, and the first end 1241 of the second transition connecting piece 124 extends out of the second output pole base 1223 and is connected to the second output pole connecting piece 1225.

[0130] Among them, when the second limiting groove formed by the second output pole base 1223 is an equal width structure, by making the first end 1241 of the second transition connecting piece 124 extend out of the second output pole base 1223 and connect with the second output pole connecting piece 1225, it is possible to avoid the second output pole connecting piece 1225 from narrowing at one end close to the second output pole base 1223, so that the second output pole connecting piece 1225 has a sufficient width, thereby ensuring the overcurrent capacity of the second output pole connecting piece 1225 and avoiding the situation of heating or even melting. When the second limiting groove formed by the second output pole base 1223 is a non-wide structure, for example, when the width of one end close to the second output pole connecting piece 1225 is relatively large, the second output pole connecting piece 1225 can also be partially located on the second output pole base 1223 with a larger width and connected with the second transition connecting piece 124. At this time, the first end 1241 of the second transition connecting piece 124 does not need to extend out of the second output pole base 1223, and the width of the second output pole connecting piece 1225 is not affected, and its overcurrent capacity is reduced.

[0131] like Figure 7~Figure 10 As shown, the first output pole connecting piece 1215 and the conducting connecting piece 125 are located on opposite sides of the first transition connecting piece 123 along the second direction Z. By making the first output pole connecting piece 1215 and the conducting connecting piece 125 located on opposite sides of the first transition connecting piece 123 along the second first direction X, that is, when the first transition connecting piece 123 is arranged, the first output pole connecting piece 1215, the transition connecting piece and the conducting connecting piece 125 can be arranged in a stacked manner in the thickness direction, so as to facilitate the connection between the first output pole connecting piece 1215, the first transition connecting piece 123 and the conducting connecting piece. Of course, the first output pole connecting piece 1215 and the conducting connecting piece 125 can also be located on the same side of the first transition connecting piece 123 along the second direction Z, and the present disclosure does not limit this.

[0132] Among them, the second output pole connecting piece 1225 and the conducting connecting piece 125 are located on opposite sides of the second transition connecting piece 124 along the second direction Z. By making the second output pole connecting piece 1225 and the conducting connecting piece 125 located on opposite sides of the second transition connecting piece 124 along the second direction Z, that is, when the second transition connecting piece 124 is set, the second output pole connecting piece 1225, the second transition connecting piece 124 and the conducting connecting piece 125 can be stacked in the thickness direction, which is convenient for the connection between the first output pole connecting piece 1215, the second transition connecting piece 124 and the conducting connecting piece. Of course, the second output pole connecting piece 1225 and the conducting connecting piece 125 can also be located on the same side of the second transition connecting piece 124 along the second direction Z, and the present disclosure does not limit this.

[0133] In one embodiment, Fig.13As shown, the first transition connecting piece 123 includes a third connecting portion 1233 and a fourth connecting portion 1234 that are arranged opposite to each other along the first direction X. The third connecting portion 1233 is connected to the first output pole connecting piece 1215, and the fourth connecting portion 1234 is connected to the conductive connecting piece 125. The fourth connecting portion 1234 is sunken toward the first end plate 1212 along the second direction Z relative to the third connecting portion 1233. By making the fourth connecting portion 1234 on the first transition connecting piece 123 sink toward the first end plate 1212 along the second direction Z relative to the third connecting portion 1233, when the first transition connecting piece 123 is connected to the conductive connecting piece 125, the first connecting portion 1253 connecting the conductive connecting piece 125 and the first transition connecting piece 123 is located on the sunken fourth connecting portion 1234, which relatively reduces the height of the first connecting portion 1253. Due to the expansion and displacement of the battery cell, the conductive connecting piece 125 will also be pulled / squeezed along with the expansion and displacement of the battery cell. The fourth connecting portion 1234 is lowered to reserve a certain space height for the buffer structure design of the conductive connecting piece 125 to prevent the conductive connecting piece 125 from being raised due to the setting of the first transition connecting piece 123. This can avoid occupying too much space in the battery pack 100, resulting in a decrease in the space utilization rate of the battery pack 100, thereby affecting the capacity of the battery pack 100; on the other hand, it can prevent the excessively high conductive connecting piece 125 from rubbing against other structures above the battery pack 100, so as to affect its structural stability and insulation reliability.

[0134] like Fig.13As shown, the second transition connecting piece 124 includes a fifth connecting portion 1243 and a sixth connecting portion 1244 arranged opposite to each other along the first direction X, the fifth connecting portion 1243 is connected to the second output pole connecting piece 1225, the sixth connecting portion 1244 is connected to the conductive connecting piece 125, and the sixth connecting portion 1244 is sunken toward the second end plate 1222 side relative to the fifth connecting portion 1243 along the second direction Z. By making the sixth connecting portion 1244 on the second transition connecting piece 124 sunken toward the second end plate 1222 side relative to the fifth connecting portion 1243 along the second direction Z, when the second transition connecting piece 124 is connected to the conductive connecting piece 125, the second connecting portion 1254 connecting the conductive connecting piece 125 and the second transition connecting piece 124 is located on the sunken sixth connecting portion 1244, and the height of the second connecting portion 1254 is relatively reduced; due to the expansion and displacement of the battery cell, the conductive connecting piece 125 will also be pulled / squeezed along with the expansion and displacement of the battery cell. In order to prevent the displacement phenomenon such as pressure, the height of the fifth connecting part 1243 is lowered to reserve a certain space height for the buffer structure design of the conductive connecting piece 125, so as to avoid the conductive connecting piece 125 from being raised due to the setting of the second transition connecting piece 124. In this way, on the one hand, it is avoided to occupy too much space of the battery pack 100, resulting in a decrease in the space utilization rate of the battery pack 100, and further affecting the capacity of the battery pack 100; on the other hand, it is avoided that the excessively high conductive connecting piece 125 rubs against other structures above the battery pack 100, so as to affect its structural stability and insulation reliability.

[0135] At the same time, when the first output pole connecting piece 1215 and the conducting connecting piece 125 are located on opposite sides of the first transition connecting piece 123 along the second direction Z, and the second output pole connecting piece 1225 and the conducting connecting piece 125 are located on opposite sides of the second transition connecting piece 124 along the second direction Z, by making the fourth connecting portion 1234 on the first transition connecting piece 123 sink relative to the third connecting portion 1233 along the second direction Z toward the first end plate 1212 side, and the sixth connecting portion 1244 on the second transition connecting piece 124 sink relative to the fifth connecting portion 1243 along the second direction Z toward the second end plate 1222 side. That is, the surface of the fourth connection part 1234 located on the first output pole base 1213 can be flush or basically flush with the surface of the first output pole connecting piece 1215, and the surface of the sixth connection part 1244 located on the second output pole base 1223 can be flush or basically flush with the surface of the second output pole connecting piece 1225, so that the conductive connecting piece 125 does not need to be redesigned due to the setting of the first transition connecting piece 123 and the second transition connecting piece 124, and the original conductive connecting piece 125 can be used, which saves a certain amount of R&D costs and improves R&D efficiency during product production and development.

[0136] During the operation of the battery cells, the battery cells will expand. When the battery cells are stacked into modules, the battery cells expand and cause the battery module 120 to deform as a whole. At this time, the distance between the end plate at the end of the battery module 120 and the battery cells becomes larger, and the transition connecting piece is pulled, which is prone to deformation and may even cause poor electrical connection.

[0137] In one embodiment, Fig.13 As shown, the first transition connecting piece 123 includes a third connecting portion 1233 and a fourth connecting portion 1234 arranged opposite to each other along the first direction X, the third connecting portion 1233 is connected to the first output pole connecting piece 1215, and the fourth connecting portion 1234 is connected to the conducting connecting piece 125; a first bending portion 1235 is also provided between the third connecting portion 1233 and the fourth connecting portion 1234 of the first transition connecting piece 123. By providing the first bending portion 1235 between the third connecting portion 1233 and the fourth connecting portion 1234 of the first transition connecting piece 123, when the first transition connecting piece 123 is subjected to a tensile force, the tensile force can be absorbed by the first bending portion 1235, thereby avoiding the first transition connecting piece 123 from being broken, resulting in failure of the electrical connection between the battery modules 120, and reducing the service life of the battery pack 100.

[0138] When the fourth connection portion 1234 of the first transition connecting piece 123 sinks toward the end plate along the second direction Z relative to the third connection portion 1233, the first bending portion 1235 is formed by bending when the fourth connection portion 1234 sinks along the second direction Z relative to the third connection portion 1233. Of course, the first bending portion 1235 can be a bending structure that is arched on a plane, and the present disclosure does not limit this.

[0139] like Fig.13 As shown, the second transition connecting piece 124 includes a fifth connecting portion 1243 and a sixth connecting portion 1244 arranged opposite to each other along the first direction X, the fifth connecting portion 1243 is connected to the second output pole connecting piece 1225, and the sixth connecting portion 1244 is connected to the conducting connecting piece 125; a second bending portion 1245 is also provided between the fifth connecting portion 1243 and the sixth connecting portion 1244 of the second transition connecting piece 124. Since the battery cell of the battery cell expands after long-term use, a tensile force in the second direction Z is applied to the second transition connecting piece 124, which may easily cause the second transition connecting piece 124 to deform or even break; by providing the second bending portion 1245 between the fifth connecting portion 1243 and the sixth connecting portion 1244 of the second transition connecting piece 124, when the second transition connecting piece 124 is subjected to a tensile force, the tensile force can be absorbed by the second bending portion 1245, thereby avoiding the second transition connecting piece 124 from breaking, which may cause the electrical connection between the battery modules 120 to fail, and reduce the service life of the battery pack 100.

[0140] When the sixth connection portion 1244 of the second transition connecting piece 124 sinks toward the end plate along the second direction Z relative to the fifth connection portion 1243, the second bending portion 1245 is formed by bending when the sixth connection portion 1244 sinks along the second direction Z relative to the fifth connection portion 1243. Of course, the second bending portion 1245 can be a bending structure that is arched on a plane, and the present disclosure does not limit this.

[0141] Among them, by setting a first bending portion 1235 on the first transition connecting piece 123, a second bending portion 1245 on the second transition connecting piece 124, and a bending structure on the conductive connecting piece 125, three bending structures capable of absorbing tensile force are formed between the adjacent first battery module 121 and the second battery module 122, thereby further improving the reliability of the electrical connection structure between the first battery module 121 and the second battery module 122.

[0142] In one embodiment, Figure 8 , Fig.10 and Fig.13 As shown, a first avoidance notch 1236 is provided on one end of the first transition connecting piece 123 along the first direction X toward the first output pole connecting piece 1215. The first avoidance notch 1236 is used to avoid the portion where the first output pole connecting piece 1215 is connected to the electrode of the battery cell. The first output pole connecting piece 1215 and the pole on the first battery cell 1211 are usually connected together by laser welding. After the first transition connecting piece 123 is provided, the first avoidance notch 1236 on the first transition connecting piece 123 can avoid the welding position of the first output pole connecting piece 1215 with the pole; at the same time, the first avoidance notch 1236 can also avoid the welding tooling for welding the first output pole connecting piece 1215 with the pole, so as to avoid interference between the first transition connecting piece 123 and the welding tooling.

[0143] Among them, Figure 8 , Fig.10 and Fig.13 As shown, a second avoidance notch 1246 is provided on one end of the second transition connecting piece 124 along the first direction X toward the second output pole connecting piece 1225. The second avoidance notch 1246 is used to avoid the portion where the second output pole connecting piece 1225 is connected to the electrode of the battery cell. The second output pole connecting piece 1225 and the pole on the second battery cell 1221 are usually connected together by laser welding. After the second transition connecting piece 124 is provided, the second avoidance notch 1246 on the second transition connecting piece 124 can avoid the welding position of the second output pole connecting piece 1225 with the pole; at the same time, the second avoidance notch 1246 can also avoid the welding tooling for welding the second output pole connecting piece 1225 with the pole, so as to avoid interference between the second transition connecting piece 124 and the welding tooling.

[0144] In one embodiment, Figure 8 As shown, the first end 1251 of the conductive connecting piece 125 and the first transition connecting piece 123 are fixedly connected to the first output pole base 1213 through the first threaded member 1261. After the first transition connecting piece 123 is arranged on the first output pole base 1213, the first connecting portion 1253 on the conductive connecting piece 125 is then stacked on the first transition connecting piece 123, and the mounting hole on the first connecting portion 1253 is aligned with the mounting hole on the first transition connecting piece 123, and then the first threaded member 1261 is passed through the mounting holes on the first connecting portion 1253 and the first transition connecting piece 123, and is threadedly connected with the threaded hole on the first output pole base 1213, so as to fix the portion where the conductive connecting piece 125 is connected to the first transition connecting piece 123 on the first output pole base 1213, so as to facilitate the installation and removal of the conductive connecting piece 125 and the first transition connecting piece 123. Of course, the portion where the conductive connecting piece 125 is connected to the first transition connecting piece 123 may also be connected by welding, bonding, clamping, etc., and the present disclosure does not impose any limitation on this.

[0145] Among them, Fig.10 As shown, the second end 1252 of the conductive connecting piece 125 and the second transition connecting piece 124 are fixedly connected to the second output pole base 1223 through the second threaded member 1262. After the second transition connecting piece 124 is arranged on the second output pole base 1223, the second connecting portion 1254 on the conductive connecting piece 125 is then stacked on the second transition connecting piece 124, and the mounting hole on the second connecting portion 1254 is aligned with the mounting hole on the second transition connecting piece 124, and then the second threaded member 1262 is passed through the mounting holes on the second connecting portion 1254 and the second transition connecting piece 124, and is threadedly connected with the threaded hole on the second output pole base 1223, so as to fix the portion of the conductive connecting piece 125 connected to the second transition connecting piece 124 on the second output pole base 1223. Of course, the portion of the conductive connecting piece 125 connected to the second transition connecting piece 124 can also be connected by welding, bonding, clamping, etc., and the present disclosure does not limit this.

[0146] In one embodiment, the first transition connecting piece 123 is welded to the first output pole connecting piece 1215. By welding the first transition connecting piece 123 to the first output pole connecting piece 1215, the connection efficiency and connection strength between the first transition connecting piece 123 and the first output pole connecting piece 1215 are high; at the same time, through welding, the first transition connecting piece 123 and the first output pole connecting piece 1215 can be fully contacted, avoiding the presence of a gap between the contact surfaces of the first transition connecting piece 123 and the first output pole connecting piece 1215, so that the contact resistance between the two is relatively low, the current capacity is improved, and the heat generation is reduced.

[0147] Among them, the first transition connecting piece 123 is provided with a first protrusion, and the first output pole connecting piece 1215 is provided with a first recessed portion, and the first protrusion is located in the first recessed portion. The first protrusion and the first recessed portion may be a welding structure left when the first transition connecting piece 123 and the first output pole connecting piece 1215 are welded. By the first protrusion being located in the first recessed portion, the connection reliability between the first transition connecting piece 123 and the first output pole connecting piece 1215 is improved.

[0148] Among them, the second transition connecting piece 124 is welded to the second output pole connecting piece 1225. By welding the second transition connecting piece 124 to the second output pole connecting piece 1225, the connection efficiency and connection strength between the second transition connecting piece 124 and the second output pole connecting piece 1225 are high; at the same time, through welding, the second transition connecting piece 124 and the second output pole connecting piece 1225 can be fully contacted, avoiding the presence of a gap between the contact surfaces of the second transition connecting piece 124 and the second output pole connecting piece 1225, so that the contact resistance between the two is relatively low, the current capacity is improved, and the heat generation is reduced.

[0149] Among them, the second transition connecting piece 124 is provided with a second protrusion, and the second output pole connecting piece 1225 is provided with a second recessed portion, and the second protrusion is located in the second recessed portion. The second protrusion and the second recessed portion can be a welding structure left when the second transition connecting piece 124 and the second output pole connecting piece 1225 are welded. By the second protrusion being located in the second recessed portion, the connection reliability between the second transition connecting piece 124 and the second output pole connecting piece 1225 is improved.

[0150] In one embodiment, the resistance of the first transition connecting piece 123 is less than or equal to the resistance of the conductive connecting piece 125, or the resistance of the second transition connecting piece 124 is less than or equal to the resistance of the conductive connecting piece 125, or the resistance of both the first transition connecting piece 123 and the second transition connecting piece 124 is less than or equal to the resistance of the conductive connecting piece 125.

[0151] Among them, the first output pole connecting piece 1215 and the second output pole connecting piece 1225 can be made of aluminum bars, and the conductive connecting piece 125 can be made of copper bars; the first transition connecting piece 123 can be made of copper bars, so that the resistance of the first transition connecting piece 123 is smaller than that of the first output pole connecting piece 1215; the second transition connecting piece 124 can also be made of copper bars, so that the resistance of the second transition connecting piece 124 is smaller than that of the second output pole connecting piece 1225; when the first transition connecting piece 123 and the second transition connecting piece 124 are made of copper bars, the resistance is the same as that of the conductive connecting piece 125. Of course, the first transition connecting piece 123 and the second transition connecting piece 124 can also be made of conductive members with a resistance between that of copper bars and aluminum bars, such as conductive members made of copper-aluminum composite materials.

[0152] When the first transition connecting piece 123 and the second transition connecting piece 124 are made of copper bars, and the first output pole connecting piece 1215 and the second output pole connecting piece 1225 are made of aluminum bars, since the materials of the copper bars and the aluminum bars are different and they are not easy to weld, brazing can be used to achieve electrical connection between copper and aluminum, and brazing generally requires melting additional solder to achieve connection between welds; however, the output pole connecting piece and the transition connecting piece are stacked, and brazing is not easy to operate and the welding is difficult, so common brazing welding cannot be used; in this regard, molecular diffusion welding is used in the present disclosure to achieve electrical connection of the stacked copper-aluminum structure; however, molecular diffusion welding has high process requirements.

[0153] In this regard, in one embodiment of the present disclosure, Fig.14 As shown, the first transition connecting piece 123 includes a first conductive layer 1237 and a second conductive layer 1238 along the second direction Z, the first conductive layer 1237 is located on the side facing the first output pole connecting piece 1215 and is made of the same material as the first output pole connecting piece 1215, and the second conductive layer 1238 is located on the side facing the conductive connecting piece 125 and is made of the same material as the conductive connecting piece 125, that is, the first transition connecting piece 123 is a composite connecting piece, the lower half of the composite connecting piece in contact with the aluminum busbar is aluminum, and the upper half in contact with the copper busbar is copper. Under the condition of meeting the overcurrent requirement, the welding between the first transition connecting piece 123 and the first output pole connecting piece 1215 can be made easier, and the electrical connection can be achieved by laser welding, thereby reducing the difficulty of welding.

[0154] Among them, Fig.14 As shown, the second transition connecting piece 124 includes a third conductive layer 1247 and a fourth conductive layer 1248 along the second direction Z, the third conductive layer 1247 is located on the side facing the second output pole connecting piece 1225 and is made of the same material as the second output pole connecting piece 1225, and the fourth conductive layer 1248 is located on the side facing the conductive connecting piece 125 and is made of the same material as the conductive connecting piece 125, that is, the second transition connecting piece 124 is a composite connecting piece, the lower half of the composite connecting piece in contact with the aluminum bus is aluminum, and the upper half in contact with the copper bus is copper. Under the condition of meeting the overcurrent requirement, the welding between the second transition connecting piece 124 and the second output pole connecting piece 1225 can be made easier, and the electrical connection can be achieved by laser welding, thereby reducing the difficulty of welding.

[0155] When the first transition connecting piece 123 and the second transition connecting piece 124 are composite connecting pieces with copper in the upper part and aluminum in the lower part, the thickness of the copper in the upper part may be greater than the thickness of the aluminum in the lower part to reduce the resistance of the composite connecting piece.

[0156] In one embodiment, the first transition connecting piece 123 and the conducting connecting piece 125 are stacked along the second direction Z, and the conducting connecting piece 125 is located on the side of the first transition connecting piece 123 away from the first end plate 1212, that is, the conducting connecting piece 125 is located above the first transition connecting piece 123. A first protrusion is provided on one of the first transition connecting piece 123 and the conducting connecting piece 125, and a first recess is provided on the other, and the first protrusion is located in the first recess. By cooperating with the first protrusion and the first recessed portion, the first transition connecting piece 123 and the conducting connecting piece 125 can be positioned and coordinated during the assembly process; if the first transition connecting piece 123 and the conducting connecting piece 125 are both smooth and flat sheets / plates, they need to be manually fixed by staff or pre-fixed with the help of external tooling during assembly, which is inconvenient for alignment operations, resulting in great difficulty in the installation and alignment of the first threaded member 1261, increasing the operating accuracy of the operator and thus reducing production efficiency. The limiting cooperation between the first protrusion and the first recessed portion facilitates the staff to pre-position the first transition connecting piece 123 and the conducting connecting piece 125 when fixing them to the module, thereby speeding up the installation and alignment of the first threaded member 1261, thereby speeding up production speed and improving production efficiency.

[0157] Among them, the second transition connecting piece 124 and the conducting connecting piece 125 are stacked along the second direction Z, and the conducting connecting piece 125 is located on the side of the second transition connecting piece 124 away from the first end plate 1212, that is, the conducting connecting piece 125 is located above the second transition connecting piece 124. A second protrusion is provided on one of the second transition connecting piece 124 and the conducting connecting piece 125, and a second recess is provided on the other, and the second protrusion is located in the second recess. Similarly, through the cooperation of the second protrusion and the second recess, the positioning and cooperation of the second transition connecting piece 124 and the conducting connecting piece 125 can be achieved during the assembly process, which is convenient for the staff to pre-position when fixing the second transition connecting piece 124 and the conducting connecting piece 125 to the module, speeding up the installation and alignment of the second threaded member 1262, thereby speeding up the production speed and improving the production efficiency.

[0158] Among them, the outer circumference of the first concave portion is greater than the outer circumference of the first protrusion, and in the direction in which the first transition connecting piece 123 and the conductive connecting piece 125 are stacked, the diameter of the first protrusion decreases toward the first concave portion, and the height of the first protrusion is greater than the depth of the first concave portion. By making the outer circumference of the first concave portion greater than the outer circumference of the first protrusion, it is equivalent to reserving a certain assembly gap / allowance, which reduces the operating accuracy of the operator and can speed up production efficiency; at the same time, the diameter of the first protrusion decreases toward the first concave portion, and the first protrusion can be regarded as a step structure with a large bottom and a small head and a trapezoidal cross section. The first protrusion with a large bottom and a small head is inserted into the first concave portion to have a guiding effect; along the height direction, the height of the first protrusion is greater than the depth of the first concave portion. Since the first screw member 1261 is tightened to press the connection downward, the first protrusion is deformed and fills the first concave portion during the press connection process, so that the conductive connecting piece 125 and the first transition connecting piece 123 are closely matched, and the structural stability is improved. In addition, the tight cooperation between the first protrusion and the first recess can increase the electrical connection area between the first transition connecting piece 123 and the conductive connecting piece 125, thereby improving the current carrying capacity, reducing heat generation, and avoiding thermal safety accidents.

[0159] Among them, the outer circumference of the second recessed part is greater than the outer circumference of the second protrusion, and in the direction in which the second transition connecting piece 124 and the conductive connecting piece 125 are stacked, the diameter of the second protrusion decreases toward the second recessed part, and the height of the second protrusion is greater than the depth of the second recessed part. By making the outer circumference of the second recessed part greater than the outer circumference of the second protrusion, it is equivalent to reserving a certain assembly gap / margin, which reduces the operating accuracy of the operator and can speed up production efficiency; at the same time, the diameter of the second protrusion decreases toward the second recessed part, and the second protrusion with a large bottom and a small head is inserted into the second recessed part to have a guiding effect; along the height direction, the height of the second protrusion is greater than the depth of the second recessed part. Since the second screw member 1262 is tightened to press the connection downward, the second protrusion is deformed and fills the second recessed part during the press connection process, so that the conductive connecting piece 125 and the second transition connecting piece 124 are closely matched, and the structural stability is improved. In addition, the tight fit between the second protrusion and the second recess can increase the electrical connection area between the second transition connecting piece 124 and the conductive connecting piece 125, thereby improving the current carrying capacity, reducing heat generation, and avoiding thermal safety accidents.

[0160] Among them, Fig.12 and Fig.13As shown, the conductive connecting piece 125 is provided with a first through hole 1257, and the first transition connecting piece 123 is provided with a second through hole 1239. The first transition connecting piece 123 and the conductive connecting piece 125 are fixed to the first end plate 1212 through the first through hole 1257 and the second through hole 1239 by means of a first screw member 1261, and the diameter of the first through hole 1257 is greater than the diameter of the second through hole 1239. Although the first protrusion and the first recessed portion can be matched for pre-positioning, if the first through hole 1257 and the second through hole 1239 are the same size, only an approximate limit position can be estimated, and then manual translation in a small range to the left and right is required to finally achieve the alignment of the first protrusion and the first recessed portion. However, since the conductive connecting piece 125 and the first transition connecting piece 123 are both made of metal, scratches will occur during translation, resulting in the generation of small metal particles. Under the working condition of the battery module 120, the small metal particles are free at various positions of the module, which can easily cause short circuit safety accidents. Therefore, by making the first through hole 1257 on the conductive connecting piece 125 larger than the second through hole 1239 on the first transition connecting piece 123, it is convenient to intuitively see whether the smaller second through hole 1239 of the first transition connecting piece 123 is aligned through the larger first through hole 1257 on the conductive connecting piece 125 when the first protrusion and the first recessed portion of the conductive connecting piece 125 and the first transition connecting piece 123 are matched, thereby reducing the operating accuracy, achieving more accurate alignment, improving production efficiency, and reducing the risk of safety accidents.

[0161] Among them, Fig.12 and Fig.13 As shown, the conductive connecting piece 125 is provided with a third through hole 1258, and the second transition connecting piece 124 is provided with a fourth through hole 1249. The second transition connecting piece 124 and the conductive connecting piece 125 are fixed to the second end plate 1222 through the third through hole 1258 and the fourth through hole 1249 by the second screw member 1262, and the diameter of the third through hole 1258 is larger than the diameter of the fourth through hole 1249. By making the third through hole 1258 on the conductive connecting piece 125 larger than the fourth through hole 1249 on the second transition connecting piece 124, it is convenient to intuitively see whether the smaller fourth through hole 1249 of the second transition connecting piece 124 is aligned through the larger third through hole 1258 on the conductive connecting piece 125 when the second protrusion and the second recess of the conductive connecting piece 125 and the second transition connecting piece 124 are matched, thereby reducing the operation precision, achieving more accurate alignment, improving production efficiency, and reducing the risk of safety accidents.

[0162] Among them, a first recessed portion is provided on the first transition connecting piece 123, and a first protruding portion is provided on the conductive connecting piece 125; the first protruding portion surrounds the first through hole 1257, and the portion of the conductive connecting piece 125 surrounding the first through hole 1257 protrudes toward the side of the first transition connecting piece 123, a first protruding portion is formed on the side facing the first transition connecting piece 123, and a first sinking platform is formed on the side away from the first transition connecting piece 123, and the first threaded member 1261 is located in the first sinking platform. Since the first threaded member 1261 on the fixed conductive connecting piece 125 and the first transition connecting piece 123 is charged, and the third threaded member 1263 on the first end plate 1212 used to define the first end plate 1212 is not charged, the creepage path of the first threaded member 1261 and the third threaded member 1263 must pass through the first side plate 12133 of the first output pole base 1213; by providing a first sink surrounding the first through hole 1257, the end of the first threaded member 1261 is located in the first sink, thereby reducing the height of the first threaded member 1261 on the first output pole base 1213, and relatively increasing the creepage distance between the first threaded member 1261 and the third threaded member 1263, thereby avoiding a short circuit between the conductive connecting piece 125 and the first end plate 1212, and further improving the safety performance of the battery pack 100.

[0163] Among them, a second recessed portion is provided on the second transition connecting piece 124, and a second protruding portion is provided on the conductive connecting piece 125; the second protruding portion surrounds the third through hole 1258, and the portion of the conductive connecting piece 125 surrounding the third through hole 1258 protrudes toward the side of the second transition connecting piece 124, and a second protruding portion is formed on the side facing the second transition connecting piece 124, and a second sinking platform is formed on the side away from the second transition connecting piece 124, and the second threaded member 1262 is located in the second sinking platform. By providing a second sinking platform surrounding the third through hole 1258, the end of the second threaded member 1262 is located in the second sinking platform, the height of the second threaded member 1262 on the second output pole base 1223 is reduced, and the creepage distance between the second threaded member 1262 and the fourth threaded member 1264 is relatively increased, thereby avoiding a short circuit between the conductive connecting piece 125 and the second end plate 1222, and further improving the safety performance of the battery pack 100.

[0164] Among them, Figure 5 and Figure 6As shown, a first base cover 1214 can be provided on the first output pole base 1213, and the first base cover 1214 and the first output pole base 1213 are both made of insulating materials. By providing the first base cover 1214, an insulating space can be formed together with the first output pole base 1213 to form an insulating covering for the first end 1251 of the conductive connecting piece 125, the second end 1232 of the first transition connecting piece 123, and the first threaded member 1261, thereby improving the insulation performance of the first end 1251 of the conductive connecting piece 125, the first end 1231 of the first transition connecting piece 123, and the first threaded member 1261 at the first output pole base 1213.

[0165] Among them, Figure 5 and Figure 6 As shown, a second base cover 1224 can be provided on the second output pole base 1223, and the second base cover 1224 and the second output pole base 1223 are both made of insulating materials. By providing the second base cover 1224, an insulating space can be formed together with the second output pole base 1223 to form an insulating coating for the second end 1252 of the conductive connecting piece 125, the second end 1242 of the second transition connecting piece 124, and the second threaded member 1262, thereby improving the insulation performance of the second end 1252 of the conductive connecting piece 125, the second end 1232 of the second transition connecting piece 124, and the second threaded member 1262 at the second output pole base 1223.

[0166] In one embodiment, Fig.12 and Fig.13 As shown, the first via hole 1257 and the third via hole 1258 on the conductive connecting piece 125 , the second via hole 1239 on the first transition connecting piece 123 , and the fourth via hole 1249 on the second transition connecting piece 124 may all be oval holes extending along the first direction X. By setting the first through hole 1257, the second through hole 1239, the third through hole 1258 and the fourth through hole 1249 as oval holes, on the one hand, the connection position of the conductive connecting piece 125 and the first transition connecting piece 123 and the second transition connecting piece 124 in the first direction X can be adjusted, thereby reducing the tolerance requirements on the components and improving the assembly accuracy; on the other hand, when the spacing between the first battery module 121 and the second battery module 122 changes due to displacement, the conductive connecting piece 125 will be affected in stretching, and the relative position between the conductive connecting piece 125 and the first transition connecting piece 123 and the second transition connecting piece 124 will change. The oval holes can absorb the change in the relative position between the conductive connecting piece 125 and the first transition connecting piece 123 and the second transition connecting piece 124, thereby preventing the first threaded member 1261 and the second threaded member 1262 from being deformed or even broken due to the shear stress caused by the position change between the conductive connecting piece 125 and the first transition connecting piece 123 and the second transition connecting piece 124.

[0167] In one embodiment, the multiple battery modules 120 include multiple groups of first battery modules 121 and second battery modules 122, and the multiple groups of first battery modules 121 and second battery modules 122 are arranged along a third direction Y; the first battery modules 121 and the second battery modules 122 in each group are provided with the above-mentioned first output pole base 1213, the second output pole base 1223 and the conductive connecting piece 125 with an insulating layer 1256; at the same time, the first battery modules 121 and the second battery modules 122 in each group can also be provided with a first transition connecting piece 123 and a second transition connecting piece 124 to further improve the safety performance of the battery pack 100.

[0168] In the embodiments of the present disclosure, the terms "first", "second", and "third" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance; the term "plurality" refers to two or more, unless otherwise expressly defined. Terms such as "installed", "connected", "connected", and "fixed" should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present disclosure can be understood according to the specific circumstances.

[0169] In the description of the embodiments of the present disclosure, it is necessary to understand that the directions or positional relationships indicated by the terms "up", "down", "left", "right", "front", "back", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore, cannot be understood as a limitation on the embodiments of the present disclosure.

[0170] In the description of this disclosure, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the implementation of the present disclosure. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0171] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. The present disclosure is intended to cover any variations, uses or adaptations of the present disclosure, which follow the general principles of the present disclosure and include common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The description and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are indicated by the appended claims.

Claims

1. A battery pack, characterized in that: include: A battery box, wherein the battery box is formed with a battery compartment; A plurality of battery modules, wherein the plurality of battery modules are located in the battery compartment; Each of the battery modules comprises a plurality of battery cells arranged along a first direction and end plates clamped at both ends of the plurality of battery cells; the plurality of battery modules comprises at least a first battery module and a second battery module arranged adjacent to each other along the first direction, a first end plate adjacent to the second battery module in the first battery module is provided with an insulating first output pole base, and a first output pole connecting piece is provided on the battery cell adjacent to the first end plate; a second end plate adjacent to the first battery module in the second battery module is provided with an insulating second output pole base, and a second output pole connecting piece is provided on the battery cell adjacent to the second end plate; the first output pole base is provided on one side of the first end plate along the second direction, and the second output pole base is provided on one side of the second end plate along the second direction, and the second direction intersects with the first direction; A conductive connecting piece, the conductive connecting piece comprising a first connecting portion, a second connecting portion and an intermediate connecting portion located between the first connecting portion and the second connecting portion, the first connecting portion being located on the first output pole base and connected to the first output pole connecting piece, the second connecting portion being located on the second output pole base and connected to the second output pole connecting piece; a first transition connecting piece, the first transition connecting piece is located on the first output pole base, the first transition connecting piece includes a third connecting portion and a fourth connecting portion which are arranged opposite to each other along the first direction, the third connecting portion is connected to the first output pole connecting piece, the fourth connecting portion is connected to the conducting connecting piece, and the fourth connecting portion is sunken toward one side of the first end plate along the second direction relative to the third connecting portion; a surface of the fourth connecting portion facing away from the first end plate along the second direction is flush or substantially flush with a surface of the first output pole connecting piece facing away from the battery cell along the second direction; a second transition connecting piece, the second transition connecting piece is located on the second output pole base, the second transition connecting piece includes a fifth connecting portion and a sixth connecting portion which are arranged opposite to each other along the first direction, the fifth connecting portion is connected to the second output pole connecting piece, the sixth connecting portion is connected to the conducting connecting piece, and the sixth connecting portion is sunken toward one side of the second end plate along the second direction relative to the fifth connecting portion; a surface of the sixth connecting portion facing away from the second end plate along the second direction is flush or substantially flush with a surface of the second output pole connecting piece facing away from the battery cell along the second direction; An insulating layer is provided on the surface of the intermediate connecting portion, and the insulating layer has an overlapping portion with the first output pole base and the second output pole base along the first direction.

2. The battery pack according to claim 1, characterized in that: At least a portion of the intermediate connection portion is in a bent structure, and the first connection portion and the second connection portion can move away from or toward each other along the first direction through the bent structure.

3. The battery pack according to claim 2, characterized in that: When the first connection portion and the second connection portion move away from each other along the first direction so that the middle connection portion in the bent structure is in a straight state, the insulating layer has an overlapping portion with the first output pole base and the second output pole base in the first direction.

4. The battery pack according to claim 2 or 3, characterized in that: The insulating layer is made of elastic material. When the first connecting portion and the second connecting portion move away from or toward each other along the first direction, the insulating layer made of elastic material can be stretched or contracted.

5. The battery pack according to claim 4, characterized in that: The insulating layer is bonded to the conductive connection sheet.

6. The battery pack according to claim 5, characterized in that: The insulating layer is an insulating tape.

7. The battery pack according to claim 1, characterized in that: The first output pole base is provided with a first extension portion extending toward one side of the first end plate, and the first extension portion and the first end plate have an overlapping portion in the second direction; and / or, the second output pole base is provided with a second extension portion extending toward one side of the second end plate, and the second extension portion and the second end plate have an overlapping portion in the second direction.

8. The battery pack according to claim 1, characterized in that: The first output pole base is provided with first side plates extending toward the second direction on both sides along the third direction; in the second direction, the height of the first side plates is greater than the thickness of the first connecting portion; and / or, the second output pole base is provided with second side plates extending toward the second direction on both sides along the third direction; in the second direction, the height of the second side plates is greater than the thickness of the second connecting portion; The third direction intersects with the first direction and the second direction.

9. The battery pack according to claim 8, characterized in that: When the first side plate is provided on the first output pole base, the first side plate is provided with a first extension portion extending along the first direction toward one side of the second end plate, and the first extension portion protrudes from the first end plate in the first direction; and / or when the second side plate is provided on the second output pole base, the second side plate is provided with a second extension portion extending along the second direction toward one side of the first end plate, and the second extension portion protrudes from the second end plate in the first direction.

10. The battery pack according to claim 1, characterized in that: The first output pole base includes a first base located between the first connecting portion and the first end plate, the first base is provided with a first protrusion extending along the first direction toward one side of the second end plate, and the first protrusion protrudes from the first end plate in the first direction; and / or, the second output pole base includes a second base located between the second connecting portion and the second end plate, the second base is provided with a second protrusion extending along the first direction toward one side of the first end plate, and the second protrusion protrudes from the second end plate in the first direction.

11. The battery pack according to claim 1, characterized in that: The resistance of the first transition connecting piece is smaller than the resistance of the first output pole connecting piece, and the resistance of the second transition connecting piece is smaller than the resistance of the second output pole connecting piece.

12. The battery pack according to claim 11, characterized in that: A first protrusion is provided on one of the first transition connecting piece and the conducting connecting piece, and a first recess is provided on the other, and the first protrusion is located in the first recess; and / or a second protrusion is provided on one of the second transition connecting piece and the conducting connecting piece, and a second recess is provided on the other, and the second protrusion is located in the second recess.

13. The battery pack according to claim 12, characterized in that: The outer circumferential size of the first recessed portion is greater than the outer circumferential size of the first protruding portion, and in the direction in which the first transition connecting piece and the conductive connecting piece are stacked, the diameter of the first protruding portion decreases toward the first recessed portion, and the height of the first protruding portion is greater than the depth of the first recessed portion; and / or, the outer circumferential size of the second recessed portion is greater than the outer circumferential size of the second protruding portion, and in the direction in which the second transition connecting piece and the conductive connecting piece are stacked, the diameter of the second protruding portion decreases toward the second recessed portion, and the height of the second protruding portion is greater than the depth of the second recessed portion.

14. The battery pack according to claim 12, characterized in that: The conductive connecting piece is provided with a first through hole, the first transition connecting piece is provided with a second through hole, the first transition connecting piece and the conductive connecting piece are fixed to the first end plate by passing through the first through hole and the second through hole by a first screw member, and the diameter of the first through hole is greater than the diameter of the second through hole; and / or, the conductive connecting piece is provided with a third through hole, the second transition connecting piece is provided with a fourth through hole, the second transition connecting piece and the conductive connecting piece are fixed to the second end plate by passing through the third through hole and the fourth through hole by a second screw member, and the diameter of the third through hole is greater than the diameter of the fourth through hole.

15. The battery pack according to claim 14, characterized in that: The first transition connecting piece is provided with the first recessed portion, and the conductive connecting piece is provided with the first raised portion; the first raised portion surrounds the first via hole, and the portion of the conductive connecting piece surrounding the first via hole protrudes toward one side of the first transition connecting piece, the first raised portion is formed on the side facing the first transition connecting piece, and a first sunken platform is formed on the side away from the first transition connecting piece, and the first threaded member is located in the first sunken platform; and / or, the second recessed portion is provided on the second transition connecting piece, and the conductive connecting piece is provided with the second raised portion; the second raised portion surrounds the third via hole, and the portion of the conductive connecting piece surrounding the third via hole protrudes toward one side of the second transition connecting piece, the second raised portion is formed on the side facing the second transition connecting piece, and a second sunken platform is formed on the side away from the second transition connecting piece, and the second threaded member is located in the second sunken platform.

16. The battery pack according to claim 1, characterized in that: The multiple battery modules include multiple groups of the first battery modules and the second battery modules, and the multiple groups of the first battery modules and the second battery modules are arranged along a third direction; the first battery modules and the second battery modules in each group are connected through the conductive connecting piece; wherein the third direction intersects with the first direction and the second direction.

17. An energy storage system, characterized in that: A battery pack comprising any one of claims 1 to 16.

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