Battery pack and energy storage system

Abstract

The utility model relates to a battery pack and an energy storage system, and relates to the technical field of energy storage. The battery pack comprises a battery box body, a plurality of battery modules, a first transition connecting piece, a second transition connecting piece and a conduction connecting piece, wherein the plurality of battery modules are positioned in the battery box body; the plurality of battery modules comprise 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, and the second battery module is provided with a second output pole base and a second output pole connecting piece; the first transition connecting piece is located on the first output pole base and connected with the first output pole connecting piece, and the resistance is smaller than that of the first output pole connecting piece; the second transition connecting piece is located on the second output electrode base and connected with the second output electrode connecting piece, and the resistance is smaller than that of the second output electrode connecting piece; the first end of the conduction connecting sheet is connected with the first transition connecting sheet, and the second end is connected with the second transition connecting sheet. And the safety performance of the battery pack is improved through the transition connecting sheet with relatively low resistance.

Description

Technical Field

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

[0002] A battery pack usually includes a plurality of battery modules, and the plurality of battery modules usually need to be electrically connected. Due to the increasing market demand for the energy density and energy size of the battery pack, the number of battery modules in the battery pack has been increasing continuously. To meet the requirement of high energy density, the current between the battery modules gradually increases, resulting in that the existing battery module structure cannot meet the overcurrent requirement, and even problems such as the electrical connection structure being fused and the electrical connection failing occur.

[0003] It should be noted that the information disclosed in the above background art section is only used to enhance the understanding of the background of the present disclosure, and thus may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Utility Model

[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, and the battery pack includes:

[0006] A battery box body, and a battery compartment is formed in the battery box body;

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

[0008] A first transition connecting piece and a second transition connecting piece, the first transition connecting piece is located on the first output pole base and is connected to the first output pole connecting piece, and the resistance of the first transition connecting piece is less than the resistance of the first output pole connecting piece; the second transition connecting piece is located on the second output pole base and is connected to the second output pole connecting piece, and the resistance of the second transition connecting piece is less than the resistance of the second output pole connecting piece;

[0009] A conducting connecting piece, the conducting connecting piece includes a first end and a second end oppositely arranged along the first direction, the first end is connected to the first transition connecting piece, and the second end is connected to the second transition connecting piece.

[0010] For the battery pack provided by the present disclosure, a first transition connecting piece is provided on the first output pole base, and a second transition connecting piece is provided on the second output pole base. The first end of the conducting connecting piece is connected and conducted with the first output pole connecting piece through the first transition connecting piece, and the second end of the conducting connecting piece is connected and conducted with the second output pole connecting piece through the second transition connecting piece; since the resistance of the first transition connecting piece is less than the resistance of the first output pole connecting piece, and the resistance of the second transition connecting piece is less than the resistance of the second output pole connecting piece, the current-carrying capacity of the corresponding electrical connectors on the first output pole base and the second output pole base is improved, avoiding the problem that the current-carrying capacity of the first output pole connecting piece located on the first output pole base and the second output pole connecting piece located on the second output pole base is relatively low after being narrowed, resulting in the output pole connecting piece being prone to serious heating and fusing, causing electrical connection failure.

[0011] In an exemplary embodiment of the present disclosure, the first output pole connecting piece and the first output pole base are spaced apart in the first direction, and one end of the first transition connecting piece extends out of the first output pole base and is connected to the first output pole connecting piece; and / or, the second output pole connecting piece and the second output pole base are spaced apart in the first direction, and one end of the second transition connecting piece extends out of the second output pole base and is connected to the second output pole connecting piece.

[0012] For the battery pack provided in this embodiment, by making one end of the first transition connecting piece extend out of the first output pole base and be connected to the first output pole connecting piece, it is possible to avoid the width reduction of the first output pole connecting piece at one end close to the first output pole base, so that the first output pole connecting piece has a sufficient width, thereby ensuring the current-carrying capacity of the first output pole connecting piece and avoiding the occurrence of heating or even fusing. By making one end of the second transition connecting piece extend out of the second output pole base and be connected to the second output pole connecting piece, it is possible to avoid the width reduction of the second output pole connecting piece at one end close to the second output pole base, so that the second output pole connecting piece has a sufficient width, thereby ensuring the current-carrying capacity of the second output pole connecting piece and avoiding the occurrence of heating or even fusing.

[0013] In an exemplary embodiment of the present disclosure, along the second direction, the first output pole base is located on one side of the first end plate, and the second output pole base is located on one side of the second end plate;

[0014] The first output terminal connecting piece and the conducting connecting piece are located on opposite sides of the first transition connecting piece along the second direction, and / or the second output terminal connecting piece and the conducting connecting piece are located on opposite sides of the second transition connecting piece along the second direction.

[0015] For the battery pack provided in this embodiment, by arranging the first output terminal connecting piece and the conducting connecting piece on opposite sides of the first transition connecting piece along the second direction, that is, when setting the first transition connecting piece, the first output terminal connecting piece, the transition connecting piece and the conducting connecting piece can be stacked in the thickness direction, which is convenient for the connection between the first output terminal connecting piece, the first transition connecting piece and the conducting connecting row piece. By arranging the second output terminal connecting piece and the conducting connecting piece on opposite sides of the second transition connecting piece along the second direction, that is, when setting the second transition connecting piece, the second output terminal connecting piece, the second transition connecting piece and the conducting connecting piece can be stacked in the thickness direction, which is convenient for the connection between the first output terminal connecting piece, the second transition connecting piece and the conducting connecting row piece.

[0016] In an exemplary embodiment of the present disclosure, a first avoidance notch is provided at one end of the first transition connecting piece facing the first output terminal connecting piece along the first direction, and the first avoidance notch is used to avoid the part where the first output terminal connecting piece is connected to the electrode of the battery cell; and / or, a second avoidance notch is provided at one end of the second transition connecting piece facing the second output terminal connecting piece along the first direction, and the second avoidance notch is used to avoid the part where the second output terminal connecting piece is connected to the electrode of the battery cell.

[0017] For the battery pack provided in this embodiment, the first avoidance notch can also avoid the welding tool for welding the first output terminal connecting piece and the pole column, preventing interference between the first transition connecting piece and the welding tool; the second avoidance notch can also avoid the welding tool for welding the second output terminal connecting piece and the pole column, preventing interference between the second transition connecting piece and the welding tool.

[0018] In an exemplary embodiment of the present disclosure, along the second direction, the first output terminal base is located on one side of the first end plate, and the second output terminal base is located on one side of the second end plate;

[0019] The first transition connection piece includes a first connection portion and a second connection portion that are oppositely arranged along the first direction. The first connection portion is connected to the first output pole connection piece, and the second connection portion is connected to the conduction connection piece. Moreover, the second connection portion sinks toward the first end plate side along the second direction relative to the first connection portion; and / or, the second transition connection piece includes a third connection portion and a fourth connection portion that are oppositely arranged along the first direction. The third connection portion is connected to the second output pole connection piece, and the fourth connection portion is connected to the conduction connection piece. Moreover, the fourth connection portion sinks toward the second end plate side along the second direction relative to the third connection portion.

[0020] In the battery pack provided in this embodiment, when the first transition connection piece is connected to the conduction connection piece, the fifth connection portion where the conduction connection piece is connected to the first transition connection piece is located on the sunken second connection portion, relatively reducing the height of the fifth connection portion; when the second transition connection piece is connected to the conduction connection piece, the sixth connection portion where the conduction connection piece is connected to the second transition connection piece is located on the sunken fourth connection portion, relatively reducing the height of the sixth connection portion.

[0021] In an exemplary embodiment of the present disclosure, the first transition connection piece includes a first connection portion and a second connection portion that are oppositely arranged along the first direction. The first connection portion is connected to the first output pole connection piece, and the second connection portion is connected to the conduction connection piece; a first bending portion is further provided between the first connection portion and the second connection portion of the first transition connection piece; and / or, the second transition connection piece includes a third connection portion and a fourth connection portion that are oppositely arranged along the first direction. The third connection portion is connected to the second output pole connection piece, and the fourth connection portion is connected to the conduction connection piece; a second bending portion is further provided between the third connection portion and the fourth connection portion of the second transition connection piece.

[0022] In the battery pack provided in this embodiment, when the first transition connection piece is subjected to a tensile force, the first bending portion can absorb the tensile force, avoiding deformation or even breakage of the first transition connection piece; when the second transition connection piece is subjected to a tensile force, the second bending portion can absorb the tensile force, avoiding deformation or even breakage of the second transition connection piece.

[0023] In an exemplary embodiment of the present disclosure, the conduction connection piece includes a fifth connection portion and a sixth connection portion that are oppositely arranged along the first direction. The fifth connection portion is connected to the first transition connection piece, and the sixth connection portion is connected to the second transition connection piece; a third bending portion is further provided between the fifth connection portion and the sixth connection portion of the conduction connection piece.

[0024] For the battery pack provided in this embodiment, when the conduction connecting piece is subjected to a tensile force, the third bending portion can absorb the tensile force, avoiding deformation or even fracture of the conduction connecting piece.

[0025] In an exemplary embodiment of the present disclosure, a first limiting groove is provided on the first output pole base, and the first transition connecting piece is located in the first limiting groove; along the third direction, the width of at least a part of the first output pole connecting piece is greater than the width of the first limiting groove; and / or, a second limiting groove is provided on the second output pole base, and the second transition connecting piece is located in the second limiting groove; along the third direction, the width of at least a part of the second output pole connecting piece is greater than the width of the second limiting groove;

[0026] 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.

[0027] For the battery pack provided in this embodiment, the width of the first output pole base is smaller than the width of the first output pole connecting piece. By providing the first transition connecting piece, it is made to replace the first output pole connecting piece and be connected to the conduction connecting piece on the first output pole base; the width of the second output pole base is smaller than the width of the second output pole connecting piece. By providing the second transition connecting piece, it is made to replace the second output pole connecting piece and be connected to the conduction connecting piece on the second output pole base.

[0028] In an exemplary embodiment of the present disclosure, the first end of the conduction connecting piece and the first transition connecting piece are fixedly connected to the first output pole base through a threaded member, and / or the second end of the conduction connecting piece and the second transition connecting piece are fixedly connected to the second output pole base through a threaded member.

[0029] For the battery pack provided in this embodiment, it is convenient for the installation and disassembly of the conduction connecting piece and the first transition connecting piece, and it is convenient for the installation and disassembly of the conduction connecting piece and the second transition connecting piece.

[0030] In an exemplary embodiment of the present disclosure, the first transition connecting piece is welded to the first output pole connecting piece, and / or the second transition connecting piece is welded to the second output pole connecting piece.

[0031] For the battery pack provided in this embodiment, the first transition connecting piece is welded to the first output pole connecting piece, with high connection efficiency, high connection strength, and relatively low contact resistance between the two; the second transition connecting piece is welded to the second output pole connecting piece, with high connection efficiency, high connection strength, and relatively low contact resistance between the two.

[0032] In an exemplary embodiment of the present disclosure, a first protrusion is provided on the first transition connection piece, a first recess is provided on the first output pole connection piece, and the first protrusion is located in the first recess; and / or, a second protrusion is provided on the second transition connection piece, a second recess is provided on the second output pole connection piece, and the second protrusion is located in the second recess.

[0033] For the battery pack provided in this embodiment, since the first protrusion is located in the first recess, the connection reliability between the first transition connection piece and the first output pole connection piece is improved; since the second protrusion is located in the second recess, the connection reliability between the second transition connection piece and the second output pole connection piece is improved.

[0034] In an exemplary embodiment of the present disclosure, the resistance of the first transition connection piece and / or the second transition connection piece is less than or equal to the resistance of the conduction connection piece.

[0035] For the battery pack provided in this embodiment, the first transition connection piece can be made of the same material as the conduction connection piece, and the second transition connection piece can be made of the same material as the conduction connection piece, thus reducing costs.

[0036] In an exemplary embodiment of the present disclosure, the first transition connection piece and / or the second transition connection piece are made of the same material as the conduction connection piece.

[0037] For the battery pack provided in this embodiment, the first transition connection piece can be made of the same material as the conduction connection piece, and the second transition connection piece can be made of the same material as the conduction connection piece, thus improving the electrical conductivity at the connection.

[0038] In an exemplary embodiment of the present disclosure, along the second direction, the first output pole base is located on one side of the first end plate, and the second output pole base is located on one side of the second end plate;

[0039] The first transition connection piece includes a first conductive layer and a second conductive layer along the second direction. The first conductive layer is located on the side facing the first output pole connection piece and is made of the same material as the first output pole connection piece, and the second conductive layer is located on the side facing the conduction connection piece and is made of the same material as the conduction connection piece; and / or, the second transition connection piece includes a third conductive layer and a fourth conductive layer along the second direction. The third conductive layer is located on the side facing the second output pole connection piece and is made of the same material as the second output pole connection piece, and the fourth conductive layer is located on the side facing the conduction connection piece and is made of the same material as the conduction connection piece.

[0040] For the battery pack provided in this embodiment, the first transition connection piece is a composite connection piece, and the second transition connection piece is a composite connection piece. The lower half layer of the composite connection piece in contact with the aluminum row is aluminum, and the upper half part in contact with the copper row is copper. Under the condition of meeting the overcurrent requirement, it can make the welding between the first transition connection piece and the first output pole connection piece easier.

[0041] In an exemplary embodiment of the present disclosure, the plurality of 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 the third direction; between the first battery module and the second battery module in each group, they are all connected through the first transition connection piece, the second transition connection piece and the conduction connection 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] For the battery pack provided in this embodiment, between adjacent battery modules, the first transition connection piece, the second transition connection piece and the conduction connection piece are all used for connection, further improving the safety performance of the battery pack.

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

[0044] For the energy storage system provided by the present disclosure, a first transition connection piece is provided on the first output pole base of the battery pack, a second transition connection piece is provided on the second output pole base, the first end of the conduction connection piece is connected and conducted with the first output pole connection piece through the first transition connection piece, and the second end of the conduction connection piece is connected and conducted with the second output pole connection piece through the second transition connection piece; since the resistance of the first transition connection piece is less than the resistance of the first output pole connection piece, and the resistance of the second transition connection piece is less than the resistance of the second output pole connection piece, the overcurrent capacity of the corresponding electrical connection components on the first output pole base and the second output pole base is improved, avoiding the problem that the first output pole connection piece is located on the first output pole base and the second output pole connection piece is located on the second output pole base, and the overcurrent capacity is relatively low after being narrowed, resulting in the output pole connection piece being prone to serious heating and fusing, causing electrical connection failure, and improving the reliability of the energy storage system.

[0045] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The accompanying drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with the present disclosure, and are used together with the specification to explain the principles of the present disclosure. Obviously, the accompanying drawings in the following description are only some embodiments of the present disclosure, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

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

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

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

[0050] Figure 4 Schematic diagram of a battery module provided for an embodiment of the present disclosure.

[0051] Figure 5 Schematic diagram of the electrical connection between the first battery module and the second battery module provided for an embodiment of the present disclosure.

[0052] Figure 6 For Figure 5 Partial enlarged view at position A in

[0053] Figure 7 Schematic diagram of the electrical connection between the first battery module and the second battery module after removing the base cover plate provided for an embodiment of the present disclosure.

[0054] Figure 8 For Figure 7 Partial enlarged view at position B in

[0055] Figure 9 For Figure 8 Explosion diagram of

[0056] Figure 10 Schematic diagram of the electrical connection structure between the first battery module and the second battery module provided for an embodiment of the present disclosure.

[0057] Figure 11 Schematic diagram of a conduction connection piece provided for an embodiment of the present disclosure.

[0058] Figure 12 Schematic diagram of a conduction connection piece provided for another embodiment of the present disclosure.

[0059] Figure 13 Schematic diagram of a conduction connection piece provided for yet another embodiment of the present disclosure.

[0060] Figure 14 Schematic diagram of the first transition connection piece and the second transition connection piece provided by an embodiment of the present disclosure.

[0061] Figure 15 Schematic diagram of the first transition connection piece and the second transition connection piece provided by another embodiment of the present disclosure.

[0062] Explanation of reference numerals:

[0063] 10, energy storage device; 20, power grid; 30, first power conversion device; 40, second power conversion device;

[0064] 100, battery pack;

[0065] 110, battery box; 111, lower box body; 112, box cover;

[0066] 120, battery module; 121, first battery module; 1211, first battery cell; 1212, first end plate; 1213, first output pole base; 1214, first base cover plate; 1215, first output pole connection piece; 1216, first cell connection piece; 1217, first tie strap; 1218, first insulating plate; 122, second battery module; 1221, second battery cell; 1222, second end plate; 1223, second output pole base; 1224, second base cover plate; 1225, second output pole connection piece; 1226, second cell connection piece; 1227, second tie strap; 1228, second insulating plate; 123, first transition connection piece; 1231, first end; 1232, second end; 1233, first connection portion; 1234, second connection portion; 1235, first bending portion; 1236, first avoidance notch; 1237, first conductive layer; 1238, second conductive layer; 124, second transition connection piece; 1241, first end; 1242, second end; 1243, third connection portion; 1244, fourth connection portion; 1245, second bending portion; 1246, second avoidance notch; 1247, third conductive layer; 1248, fourth conductive layer; 125, conduction connection piece; 1251, first end; 1252, second end; 1253, fifth connection portion; 1254, sixth connection portion; 1255, third bending portion; 1256, insulating layer; 126, screw. Detailed implementation manners

[0067] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various 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 thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. Like reference numerals in the figures denote the same or similar structures, and thus their detailed descriptions will be omitted.

[0068] Since the energy required by people has strong temporality and spatiality, in order to rationally utilize energy and improve utilization efficiency, it is necessary to store an energy form in the same energy form or convert it into another energy form through a medium or device, and then release it in a specific energy form based on future applications.

[0069] Currently, green energy mainly includes light energy, wind energy, etc. However, problems such as strong intermittency and large volatility are common in light energy and wind energy, which can cause voltage instability in the green power grid (not enough electricity during peak electricity consumption and too much electricity during low electricity consumption). Unstable voltage can damage the power, so the problem of "abandoning wind and light" may be caused due to insufficient electricity demand or insufficient grid acceptance capacity.

[0070] To solve the problems of insufficient electricity demand or insufficient grid acceptance capacity, it is necessary to rely on energy storage devices. That is, through energy storage devices, electrical energy is converted into other forms of energy and stored by physical or chemical means, and then the energy stored in the energy storage device is converted into electrical energy and released when needed. Simply put, the energy storage device is similar to a large "portable charger", which stores electrical energy when light energy and wind energy are sufficient and releases the stored electrical energy when needed.

[0071] Currently, the application scenarios of energy storage (i.e., energy storage) are relatively wide, including power generation side energy storage, grid side energy storage, renewable energy grid connection energy storage, and user side energy storage, etc. The types of corresponding energy storage devices include:

[0072] (1) Large-scale energy storage power stations applied in energy storage scenarios on the power generation side such as wind power and photovoltaic power stations can assist renewable energy power generation to meet grid connection requirements and improve the utilization rate of renewable energy at the same time; as a high-quality active / reactive power regulation power source on the power supply side, the energy storage power station realizes the load matching of electrical energy in time and space, enhances the consumption capacity of renewable energy, reduces instantaneous power changes, reduces the impact on the power grid, improves the problem of new energy power generation consumption, and is of great significance in grid system standby, alleviating the power supply pressure during peak loads, and peak shaving and frequency modulation;

[0073] (2) Large-scale energy storage containers applied in energy storage scenarios on the grid side, whose main functions are peak shaving, frequency modulation, and alleviating grid congestion peak shaving. They can achieve peak shaving and valley filling of the electricity load, that is, charging the energy storage battery during the low electricity load period and releasing the stored electricity during the peak electricity load period, so as to achieve the balance between power production and consumption. For example, the energy storage power station system;

[0074] (3) Small and medium-sized energy storage cabinets applied to industrial and commercial energy storage scenarios (banks, shopping malls, etc.) on the user side and household small energy storage boxes applied to household energy storage scenarios on the user side mainly function as self-use of electricity generated, peak shaving and valley filling, capacity charge management, and improvement of 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 combination with distributed photovoltaics. Due to the large price difference in electricity charges at peak and valley positions according to electricity consumption 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 high electricity price period, they release the electricity in the energy storage devices for use to achieve the purpose of saving electricity charges. In addition, energy storage needs to be configured in fields such as communication base stations and data centers for backup power supplies. Moreover, in remote areas and areas with high incidence of natural disasters such as earthquakes and hurricanes, the existence of household energy storage devices is equivalent to users providing backup power supplies for themselves and the power grid, eliminating the inconvenience caused by frequent power outages due to disasters or other reasons.

[0075] Figure 1 Schematic diagram of an energy storage system provided by 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 of the present disclosure is not limited to its energy storage scenario on the power generation / distribution side, and can also be applied to scenarios such as the industrial and commercial side or the user side.

[0076] As Figure 1 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 electrical energy, connect to the power grid 20, and supply power for use on the power distribution side of the power grid; when the power generation of the first power conversion device 30 and the second power conversion device 40 is excessive during low power consumption loads, the excess power is stored in the energy storage device 10 to reduce the curtailment rate of wind and light and improve the problem of new energy power generation accommodation; when the power consumption load is high, the power grid issues an instruction to transmit the power stored in the energy storage device 10 and the power grid 20 in a grid-connected mode to supply power for use on the power consumption side, providing various services such as peak shaving, frequency modulation, and standby for the operation of the power grid 20, giving full play to the peak shaving role of the power grid 20, promoting peak shaving and valley filling of the power grid 20, and alleviating the power supply pressure of the power grid 20.

[0077] 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.

[0078] Combined with the above-mentioned cases of energy storage by physical or electrochemical means, taking electrochemical energy storage as an example, the energy storage device 10 includes at least one chemical battery, using chemical elements in the chemical battery as the energy storage medium to realize the charging and discharging process through chemical reactions or changes of the energy storage medium. Simply put, the electrical energy generated by light energy and wind energy is stored in at least one group of chemical batteries through chemical reactions or changes of the energy storage medium, and when the use of external electrical energy reaches a peak, the electrical energy stored in at least one group of chemical batteries is released through chemical reactions or changes of the energy storage medium for use, or transferred to places with a shortage of electrical energy for reuse.

[0079] Among them, the energy storage device 10 can be a battery pack, an energy storage box, an energy storage cabinet, etc. including battery cells. The battery cells can be lithium-ion secondary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, magnesium-ion batteries, etc., and the battery cells can be in the shape of a cylinder, a flat body, a cuboid, etc., and the embodiments of the present disclosure do not limit this.

[0080] Such as Figure 2 and Figure 3 As shown, taking the energy storage device 10 as the battery pack 100 as an example, the battery pack 100 includes a battery box body 110 and a plurality of battery modules 120. The battery box body 110 includes a lower box body 111 and a box cover 112, and the box cover 112 is fixedly / detachably connected to the lower box body 111 to enclose a battery compartment; a plurality of battery modules 120 are located in the battery compartment.

[0081] Among them, the number of battery modules 120 accommodated in the battery compartment of the battery box body 110 can be at least one, such as one, two, four, five, six, seven, eight or more, and the more the number of battery modules 120, the higher the capacity of the battery pack 100, and thus it is easier to meet the market demand. Exemplarily, as Figure 4 shown, there are two rows along the length direction of the battery box body 110 and four columns along the width direction of the battery box body 110 in the battery compartment of the battery box body 110, totaling eight battery modules 120.

[0082] Among them, each battery module 120 may include a pair of end plates oppositely arranged 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 can be fixed by tying tools such as cable ties. The plurality of battery cells are arranged along the length direction of the battery box body, and the plurality of battery cells are connected by cell connection sheets to realize series / parallel electrical connection between the plurality of battery cells. Exemplarily, as Figure 5 and Figure 6As shown in the figure, the first battery module 121 includes a pair of first end plates 1212 arranged oppositely, 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 box 110, and the plurality of first battery cells 1211 are connected by a first cell connection piece 1216 to achieve 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 oppositely, 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 box 110, and the plurality of second battery cells 1221 are connected by a second cell connection piece 1226 to achieve series / parallel electrical connection between the plurality of second battery cells 1221.

[0083] Among them, the plurality of battery cells are connected in series in sequence. At this time, each cell connection piece is respectively connected to the electrode terminals with different polarities on two battery cells; alternatively, the plurality of battery cells are grouped in pairs and connected in parallel, and then the groups are connected in series. At this time, each cell connection piece is first respectively connected to the electrode terminals with the same polarity on two battery cells, and then connected to the electrode terminals with the opposite polarity on the other two battery cells.

[0084] Among them, the outer walls of the battery cells can be coated with insulating films to avoid potential safety hazards caused by the leakage of the battery cells through the housing; since the end plates are usually made of aluminum or other structures with a certain strength, such as Figure 5 and Figure 6 As shown in the figure, 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 the burrs or protruding structures on the first end plate 1212 from piercing the insulating film on the first battery cell 1211, and at the same time avoid the situation that the first end plate 1212 is electrified after the first battery cell 1211 leaks electricity; at the same time, since the first battery cell 1211 is electrified and the first end plate 1212 is not electrified, 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, ensuring that the first end plate 1212 is not electrified, thereby avoiding the electrification of the battery box 110 and improving the safety of the operation of the staff.

[0085] 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 raised 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 when the second battery cell 1221 leaks electricity; at the same time, since the second battery cell 1221 is charged and the second end plate 1222 is not charged, by providing 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 avoiding the battery box 110 from being charged and improving the safety of the staff's operation.

[0086] In the related art, the end plates at both ends of the battery module are usually cast aluminum end plates. An output pole base is provided on the end plate, an output pole connecting piece is placed on the output pole base, and a copper row is connected to the output pole connecting piece. The output pole connecting piece and the end plate are insulated through the output pole base to prevent the two from contacting and causing a short circuit. Usually, from the perspectives of material cost, battery pack weight, and space utilization, the width of the output pole base is relatively small. When the output pole connecting piece needs to be placed on the output pole base, the output pole connecting piece needs to be set in a shape with different widths, that is, the width of the end of the output pole connecting piece close to the output pole base is reduced to be placed on the output pole base.

[0087] However, in the battery module, when the battery cells are electrically connected in parallel or in series-parallel, the current of the output pole connecting piece at the output end will combine the parallel currents into one path, and the current at the output end will be larger than the current when only the series connection method is used. Therefore, when the width of the output pole connecting piece becomes narrower at the output end, the overcurrent channel also becomes narrower, which cannot meet the overcurrent requirements of the battery module connected in parallel or in series-parallel, and is likely to cause the output pole connecting piece to heat up rapidly or even melt, resulting in the failure of the electrical connection.

[0088] In view of the above technical problems, the embodiments of the present disclosure provide a battery pack, as Figures 2 to 10 shown. The battery pack 100 includes: a battery box 110, a plurality of battery modules 120, a first transition connecting piece 123, a second transition connecting piece 124, and a conduction connecting piece 125. Each battery module 120 includes a plurality of battery cells arranged along the first direction X and end plates clamped at both ends of the plurality of battery cells; 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; among them, the first direction X is the length direction of the battery pack 100. Hereinafter, the present disclosure takes the first battery module 121 and the second battery module 122 as examples to discuss in detail the electrical connection structure between adjacent battery modules 120.

[0089] Among them, an insulated first output pole base 1213 is provided on a first end plate 1212 of the first battery module 121 adjacent to the second battery module 122, and a first output pole connecting piece 1215 is provided on a first battery cell 1211 adjacent to the first end plate 1212; an insulated second output pole base 1223 is provided on a second end plate 1222 of the second battery module 122 adjacent to the first battery module 121, and a second output pole connecting piece 1225 is provided on a second battery cell 1221 adjacent to the second end plate 1222.

[0090] Among them, a 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; a 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 conduction connecting piece 125 includes a first end 1251 and a second end 1252 oppositely arranged along the first direction X, 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.

[0091] For the battery pack 100 provided by the present disclosure, the first transition connecting piece 123 is provided on the first output pole base 1213, the second transition connecting piece 124 is provided on the second output pole base 1223, the first end 1251 of the conduction connecting piece 125 is connected and conducted with the first output pole connecting piece 1215 through the first transition connecting piece 123, and the second end 1252 of the conduction 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 the resistance of the first output pole connecting piece 1215, and the resistance of the second transition connecting piece 124 is less than the resistance of the second output pole connecting piece 1225, the overcurrent capacity of the corresponding electrical connectors on the first output pole base 1213 and the second output pole base 1223 is improved, and it is avoided that the overcurrent capacity of the first output pole connecting piece 1215 located on the first output pole base 1213 and the second output pole connecting piece 1225 located on the second output pole base 1223 is relatively low after being narrowed, resulting in serious heating and melting of the output pole connecting piece and causing the problem of electrical connection failure.

[0092] 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 a 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 less 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 in a shape with different widths, that is, the width of the end of the first output pole connecting piece 1215 close to the first output pole base 1213 is narrowed to be placed on the first output pole base 1213; by providing the first transition connecting piece 123, it is made to replace the first output pole connecting piece 1215 and be located on the first output pole base 1213 to be connected to the conduction connecting piece 125. Wherein, the third direction Y is the width direction of the battery pack 100.

[0093] Specifically, 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 a 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 less 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 in a shape with different widths, that is, the width of the end of the second output pole connecting piece 1225 close to the second output pole base 1223 is narrowed to be placed on the second output pole base 1223; by providing the second transition connecting piece 124, it is made to replace the second output pole connecting piece 1225 and be located on the second output pole base 1223 to be connected to the conduction connecting piece 125.

[0094] Specifically, the first output pole connecting piece 1215 and the first output pole base 1213 are spaced apart in the first direction X. The first transition connecting piece 123 includes a first end 1231 and a second end 1232 which are oppositely arranged. The first end 1231 of the first transition connecting piece 123 extends out of the first output pole base 1213 to be connected to the first output pole connecting piece 1215.

[0095] Among them, when the first limiting groove formed by the first output pole base 1213 is of an equal-width structure, by extending the first end 1231 of the first transition connecting piece 123 out of the first output pole base 1213 to connect with the first output pole connecting piece 1215, it is possible to prevent 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 sufficient width, thereby ensuring the current-carrying capacity of the first output pole connecting piece 1215 and avoiding situations such as overheating or even fusing. When the first limiting groove formed by the first output pole base 1213 is of a non-uniform-width 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 to connect 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, as long as it does not affect the width of the first output pole connecting piece 1215 and reduce its current-carrying capacity.

[0096] Specifically, the second output pole connecting piece 1225 and the second output pole base 1223 are arranged at intervals in the first direction X. The second transition connecting piece 124 includes a first end 1241 and a second end 1242 arranged opposite to each other. The first end 1241 of the second transition connecting piece 124 extends out of the second output pole base 1223 to connect with the second output pole connecting piece 1225.

[0097] Among them, when the first limiting groove formed by the second output pole base 1223 is of an equal-width structure, by extending the first end 1241 of the second transition connecting piece 124 out of the second output pole base 1223 to connect with the second output pole connecting piece 1225, it is possible to prevent 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 sufficient width, thereby ensuring the current-carrying capacity of the second output pole connecting piece 1225 and avoiding situations such as overheating or even fusing. When the first limiting groove formed by the second output pole base 1223 is of a non-uniform-width 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 to connect 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, as long as it does not affect the width of the second output pole connecting piece 1225 and reduce its current-carrying capacity.

[0098] As Figures 7 to 9 shown, along the second direction Z, the first output pole base 1213 is located on one side of the first end plate 1212, and the second output pole base 1223 is located on one side of the second end plate 1222. Among them, the second direction Z is the height direction of the battery pack 100.

[0099] Among them, 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 setting the first transition connecting piece 123, the first output pole connecting piece 1215, the transition connecting piece, 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 first transition connecting piece 123, and the conducting connecting strip. 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.

[0100] 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 setting the second transition connecting piece 124, 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 strip. 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.

[0101] In one embodiment, as Figures 8 to 14As shown, the first transition connection piece 123 includes a first connection part 1233 and a second connection part 1234 that are oppositely arranged along the first direction X. The first connection part 1233 is connected to the first output pole connection piece 1215, and the second connection part 1234 is connected to the conduction connection piece 125. Moreover, the second connection part 1234 sinks toward the end plate side relative to the first connection part 1233 along the second direction Z. By making the second connection part 1234 on the first transition connection piece 123 sink toward the end plate side relative to the first connection part 1233 along the second direction Z, when the conduction connection piece 125 is connected to the first transition connection piece 123, the fifth connection part 1253 where the conduction connection piece 125 is connected to the first transition connection piece 123 is located on the sunken second connection part 1234, relatively reducing the height of the fifth connection part 1253. Due to the displacement caused by the expansion of the battery cell, the conduction connection piece 125 will also undergo displacement phenomena such as pulling / squeezing along with the displacement of the expansion of the battery cell. Reducing the height of the fifth connection part 1253 reserves a certain space height for the buffer structure design of the conduction connection piece 125, avoiding the increase in the position of the conduction connection piece 125 caused by the setting of the first transition connection piece 123. On the one hand, this avoids occupying too much space in the battery pack 100, resulting in a reduction 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 avoids friction between the overly high conduction connection piece 125 and other structures above in the battery pack 100, thus affecting its structural stability and insulation reliability.

[0102] As Figures 8 to 14As shown, the second transition connection piece 124 includes a third connection part 1243 and a fourth connection part 1244 which are oppositely arranged along the first direction X. The third connection part 1243 is connected to the second output pole connection piece 1225, and the fourth connection part 1244 is connected to the conduction connection piece 125. And the fourth connection part 1244 sinks towards the end plate side along the second direction Z relative to the third connection part 1243. By making the fourth connection part 1244 on the second transition connection piece 124 sink towards the end plate side along the second direction Z relative to the third connection part 1243, when the conduction connection piece 125 is connected to the second transition connection piece 124, the sixth connection part 1254 where the conduction connection piece 125 is connected to the second transition connection piece 124 is located on the sunken fourth connection part 1244, relatively reducing the height of the sixth connection part 1254. Due to the displacement caused by the expansion of the battery cell, the conduction connection piece 125 will also have displacement phenomena such as pulling / squeezing along with the displacement of the battery cell expansion. Reducing the height of the fifth connection part 1253 reserves a certain space height for the buffer structure design of the conduction connection piece 125, avoiding the increase in the position of the conduction connection piece 125 caused by the setting of the second transition connection piece 124. On the one hand, this avoids occupying too much space in the battery pack 100, resulting in a reduction 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 avoids friction between the too-high conduction connection piece 125 and other structures above in the battery pack 100, so as to affect its structural stability and insulation reliability.

[0103] Meanwhile, when the first output pole connection piece 1215 and the conduction connection piece 125 are on the opposite sides of the first transition connection piece 123 along the second direction Z, and the second output pole connection piece 1225 and the conduction connection piece 125 are on the opposite sides of the second transition connection piece 124 along the second direction Z, by making the second connection part 1234 on the first transition connection piece 123 sink towards the end plate side along the second direction Z relative to the first connection part 1233, and making the fourth connection part 1244 on the second transition connection piece 124 sink towards the end plate side along the second direction Z relative to the third connection part 1243, that is, the surface of the second connection part 1234 located on the first output pole base 1213 can be flush or substantially flush with the surface of the first output pole connection piece 1215, and the surface of the fourth connection part 1244 located on the second output pole base 1223 can be flush or substantially flush with the surface of the second output pole connection piece 1225. Thus, the conduction connection piece 125 does not need to have its structure redesigned due to the settings of the first transition connection piece 123 and the second transition connection piece 124, and the original conduction connection piece 125 can be used, saving a certain amount of R & D costs and improving the R & D efficiency during the product production and R & D process.

[0104] During the operation of the battery cell, the battery cell will expand. When the battery cells are stacked into a module, the expansion of the battery cells will cause the overall deformation of the battery module 120. At this time, the distance between the end plate at the end of the battery module 120 and the battery cell becomes larger, and the transition connecting piece is pulled, which is prone to deformation and even lead to poor electrical connection.

[0105] In one embodiment, as Figure 8 and Figure 14 shown, the first transition connecting piece 123 includes a first connecting portion 1233 and a second connecting portion 1234 which are oppositely arranged along the first direction X. The first connecting portion 1233 is connected to the first output pole connecting piece 1215, and the second connecting portion 1234 is connected to the conduction connecting piece 125; a first bending portion 1235 is further provided between the first connecting portion 1233 and the second connecting portion 1234 of the first transition connecting piece 123. By providing the first bending portion 1235 between the first connecting portion 1233 and the second 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 through the first bending portion 1235, avoiding the situation that the first transition connecting piece 123 breaks, resulting in the electrical connection failure between the battery modules 120 and reducing the service life of the battery pack 100.

[0106] Wherein, when the second connecting portion 1234 of the first transition connecting piece 123 sinks toward the end plate side relative to the first connecting portion 1233 along the second direction Z, the first bending portion 1235 is formed by bending when the second connecting portion 1234 sinks relative to the first connecting portion 1233 along the second direction Z. Of course, the first bending portion 1235 can be a bending structure arched on a plane, and the present disclosure does not limit this.

[0107] As Figure 8 and Figure 14 shown, the second transition connecting piece 124 includes a third connecting portion 1243 and a fourth connecting portion 1244 which are oppositely arranged along the first direction X. The third connecting portion 1243 is connected to the second output pole connecting piece 1225, and the fourth connecting portion 1244 is connected to the conduction connecting piece 125; a second bending portion 1245 is further provided between the third connecting portion 1243 and the fourth connecting portion 1244 of the second transition connecting piece 124. Since the battery cells of the battery monomers have an expansion phenomenon after long-term use, a tensile force in the second direction Z is caused to the second transition connecting piece 124, which is prone to deformation and even fracture of the second transition connecting piece 124; by providing the second bending portion 1245 between the third connecting portion 1243 and the fourth 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 through the second bending portion 1245, avoiding the situation that the second transition connecting piece 124 breaks, resulting in the electrical connection failure between the battery modules 120 and reducing the service life of the battery pack 100.

[0108] Wherein, when the fourth connecting portion 1244 of the second transition connecting piece 124 sinks toward the end plate side along the second direction Z relative to the third connecting portion 1243, the second bending portion 1245 is formed by bending when the fourth connecting portion 1244 sinks relative to the third connecting portion 1243 along the second direction Z. Of course, the second bending portion 1245 may be a bending structure that arches on a plane, and the present disclosure does not limit this.

[0109] As Figures 8 to 12 shown, the conducting connecting piece 125 includes a fifth connecting portion 1253 and a sixth connecting portion 1254 that are oppositely arranged along the first direction X. The fifth connecting portion 1253 is connected to the first transition connecting piece 123, and the sixth connecting portion 1254 is connected to the second transition connecting piece 124; a third bending portion 1255 is further provided between the fifth connecting portion 1253 and the sixth connecting portion 1254 of the conducting connecting piece 125. Since the battery cells of the battery monomer expand after long-term use, the conducting connecting piece 125 will be subjected to a tensile force from the first transition connecting piece 123 and the second transition connecting piece 124, causing a tensile force on the conducting connecting piece 125 in the second direction Z, which easily leads to deformation or even fracture of the conducting connecting piece 125; by providing the third bending portion 1255, when the conducting connecting piece 125 is subjected to a tensile force, the third bending portion 1255 can absorb the tensile force, avoiding deformation or even fracture of the conducting connecting piece 125. Of course, the conducting connecting piece 125 may also be as Figure 11 shown without a bending structure, and the present disclosure does not limit this.

[0110] Wherein, by providing the first bending portion 1235 on the first transition connecting piece 123, the second bending portion 1245 on the second transition connecting piece 124, and the third bending portion 1255 on the conducting 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, further improving the reliability of the electrical connection structure between the first battery module 121 and the second battery module 122.

[0111] In one embodiment, as Figure 13 shown, an insulating layer 1256 is provided in the region between the fifth connecting portion 1253 and the sixth connecting portion 1254 of the conducting connecting piece 125. Since the end plates at both ends of the battery module 120 are usually conductive metal end plates, there is a risk of short circuit between the conducting connecting piece 125 and the end plate, seriously affecting the safety performance of the battery pack 100; by providing the insulating layer 1256 in the region between the fifth connecting portion 1253 and the sixth connecting portion 1254 of the conducting connecting piece 125, the insulation performance between the conducting connecting piece 125 and the metal end plate is improved, reducing the risk of short circuit between the conducting connecting piece 125 and the end plate, and improving the safety performance of the battery pack 100.

[0112] Among them, the insulating layer 1256 can be an insulating tape and is pasted on the surface of the conduction connecting piece 125 that needs to be insulated; the insulating layer 1256 can also be a coating layer, and the surface of the conduction connecting piece 125 that needs to be insulated is coated with an insulating material; the present disclosure does not limit the specific material and setting method of the insulating layer 1256.

[0113] In one embodiment, as Figure 8 and Figure 14 shown, a first avoidance notch 1236 is provided at one end of the first transition connecting piece 123 along the first direction X facing the first output pole connecting piece 1215. The first avoidance notch 1236 is used to avoid the part 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 form an avoidance of the welding position of the first output pole connecting piece 1215 with the pole; at the same time, the welding tool for welding the first output pole connecting piece 1215 to the pole can also be avoided through the first avoidance notch 1236, so as to avoid interference between the first transition connecting piece 123 and the welding tool.

[0114] As Figure 8 and Figure 14 shown, a second avoidance notch 1246 is provided at one end of the second transition connecting piece 124 along the first direction X facing the second output pole connecting piece 1225. The second avoidance notch 1246 is used to avoid the part 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 form an avoidance of the welding position of the second output pole connecting piece 1225 with the pole; at the same time, the welding tool for welding the second output pole connecting piece 1225 to the pole can also be avoided through the second avoidance notch 1246, so as to avoid interference between the second transition connecting piece 124 and the welding tool.

[0115] In one embodiment, as Figure 8 and Figure 9As shown, the first end 1251 of the conduction connecting piece 125 and the first transition connecting piece 123 are fixedly connected to the first output pole base 1213 through threaded parts. After the first transition connecting piece 123 is arranged on the first output pole base 1213, then the fifth connecting part 1253 on the conduction connecting piece 125 is stacked on the first transition connecting piece 123, and the mounting holes on the fifth connecting part 1253 are aligned with the mounting holes on the first transition connecting piece 123. Then, a screw 126 is used to pass through the mounting holes on the fifth connecting part 1253 and the first transition connecting piece 123 and is threadedly connected to the threaded hole on the first output pole base 1213, so as to fix the part where the conduction connecting piece 125 is connected to the first transition connecting piece 123 on the first output pole base 1213, which is convenient for the installation and disassembly of the conduction connecting piece 125 and the first transition connecting piece 123. Of course, the part where the conduction connecting piece 125 is connected to the first transition connecting piece 123 can also be connected by welding, bonding, clamping and other methods, and the present disclosure does not limit this.

[0116] As Figure 8 and Figure 9 shown, the second end 1252 of the conduction connecting piece 125 and the second transition connecting piece 124 are fixedly connected to the second output pole base 1223 through threaded parts. After the second transition connecting piece 124 is arranged on the second output pole base 1223, then the sixth connecting part 1254 on the conduction connecting piece 125 is stacked on the second transition connecting piece 124, and the mounting holes on the sixth connecting part 1254 are aligned with the mounting holes on the second transition connecting piece 124. Then, a screw 126 is used to pass through the mounting holes on the sixth connecting part 1254 and the second transition connecting piece 124 and is threadedly connected to the threaded hole on the second output pole base 1223, so as to fix the part where the conduction connecting piece 125 is connected to the second transition connecting piece 124 on the second output pole base 1223. Of course, the part where the conduction connecting piece 125 is connected to the second transition connecting piece 124 can also be connected by welding, bonding, clamping and other methods, and the present disclosure does not limit this.

[0117] 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 between the first transition connecting piece 123 and the first output pole connecting piece 1215 is high, and the connection strength is high; at the same time, through welding, the first transition connecting piece 123 and the first output pole connecting piece 1215 can be in full contact, avoiding gaps 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, improving the overcurrent capacity and reducing the heat generation.

[0118] Among them, a first convex portion is provided on the first transition connection piece 123, and a first concave portion is provided on the first output pole connection piece 1215, and the first convex portion is located in the first concave portion. The first convex portion and the first concave portion may be welding structures left when the first transition connection piece 123 and the first output pole connection piece 1215 are welded. By the first convex portion being located in the first concave portion, the connection reliability between the first transition connection piece 123 and the first output pole connection piece 1215 is improved.

[0119] Among them, the second transition connection piece 124 is welded to the second output pole connection piece 1225. By welding the second transition connection piece 124 and the second output pole connection piece 1225, the connection efficiency between the second transition connection piece 124 and the second output pole connection piece 1225 is high, and the connection strength is high; at the same time, through welding, the second transition connection piece 124 and the second output pole connection piece 1225 can be in full contact, avoiding gaps between the contact surfaces of the second transition connection piece 124 and the second output pole connection piece 1225, so that the contact resistance between the two is relatively low, improving the overcurrent capacity and reducing the heat generation.

[0120] Among them, a second convex portion is provided on the second transition connection piece 124, and a second concave portion is provided on the second output pole connection piece 1225, and the second convex portion is located in the second concave portion. The second convex portion and the second concave portion may be welding structures left when the second transition connection piece 124 and the second output pole connection piece 1225 are welded. By the second convex portion being located in the second concave portion, the connection reliability between the second transition connection piece 124 and the second output pole connection piece 1225 is improved.

[0121] In one embodiment, the resistance of the first transition connection piece 123 is less than or equal to the resistance of the conduction connection piece 125, or the resistance of the second transition connection piece 124 is less than or equal to the resistance of the conduction connection piece 125, or the resistances of both the first transition connection piece 123 and the second transition connection piece 124 are less than or equal to the resistance of the conduction connection piece 125.

[0122] Among them, the first output pole connection piece 1215 and the second output pole connection piece 1225 may adopt aluminum bars, and the conduction connection piece 125 may adopt a copper bar; the first transition connection piece 123 may adopt a copper bar so that the resistance of the first transition connection piece 123 is less than that of the first output pole connection piece 1215; the second transition connection piece 124 may also adopt a copper bar so that the resistance of the second transition connection piece 124 is less than that of the second output pole connection piece 1225; when the first transition connection piece 123 and the second transition connection piece 124 adopt copper bars, the resistance is the same as that of the conduction connection piece 125 at this time. Of course, the first transition connection piece 123 and the second transition connection piece 124 may also adopt conductive members with a resistance between that of a copper bar and an aluminum bar, such as a copper-aluminum composite conductive member.

[0123] When the first transition connection piece 123 and the second transition connection piece 124 are made of copper bars, and the first output pole connection piece 1215 and the second output pole connection piece 1225 are made of aluminum bars, since the materials of the copper bars and the aluminum bars are different and they are not easily welded, a brazing method can be used to achieve the electrical connection between copper and aluminum. Generally, brazing requires melting additional solder to achieve the connection between the workpieces. However, the output pole connection pieces and the transition connection pieces are stacked. If brazing is used, it is not easy to operate and the welding difficulty is high. Therefore, the common brazing welding cannot be used. In this regard, in the present disclosure, molecular diffusion welding is used to achieve the electrical connection of the stacked copper-aluminum structure. However, molecular diffusion welding has high requirements for the process.

[0124] In this regard, in an embodiment of the present disclosure, as Figure 15 shown, the first transition connection 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 connection piece 1215 and has the same material as the first output pole connection piece 1215. The second conductive layer 1238 is located on the side facing the conduction connection piece 125 and has the same material as the conduction connection piece 125. That is, the first transition connection piece 123 is a composite connection piece. The lower half of the composite connection piece in contact with the aluminum bar is aluminum, and the upper half in contact with the copper bar is copper. Under the condition of meeting the overcurrent requirement, it can make the welding between the first transition connection piece 123 and the first output pole connection piece 1215 easier, and the electrical connection can be achieved by laser welding, reducing the welding difficulty.

[0125] Among them, as Figure 15 shown, the second transition connection 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 connection piece 1225 and has the same material as the second output pole connection piece 1225. The fourth conductive layer 1248 is located on the side facing the conduction connection piece 125 and has the same material as the conduction connection piece 125. That is, the second transition connection piece 124 is a composite connection piece. The lower half of the composite connection piece in contact with the aluminum bar is aluminum, and the upper half in contact with the copper bar is copper. Under the condition of meeting the overcurrent requirement, it can make the welding between the second transition connection piece 124 and the second output pole connection piece 1225 easier, and the electrical connection can be achieved by laser welding, reducing the welding difficulty.

[0126] Among them, when the first transition connection piece 123 and the second transition connection piece 124 adopt a composite connection piece with copper in the upper half and aluminum in the lower half, the thickness of the copper in the upper half can be greater than the thickness of the aluminum in the lower half to reduce the resistance of the composite connection piece.

[0127] In an embodiment, as Figure 5 and Figure 6As shown, a first base cover plate 1214 may be provided on the first output pole base 1213. Both the first base cover plate 1214 and the first output pole base 1213 are made of insulating materials. By providing the first base cover plate 1214, an insulating space can be formed in cooperation with the first output pole base 1213 to form an insulating coating for the first end 1251 of the conduction 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 conduction 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.

[0128] Among them, as Figure 5 and Figure 6 shown, a second base cover plate 1224 may be provided on the second output pole base 1223. Both the second base cover plate 1224 and the second output pole base 1223 are made of insulating materials. By providing the second base cover plate 1224, an insulating space can be formed in cooperation with the second output pole base 1223 to form an insulating coating for the second end 1252 of the conduction 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 conduction 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.

[0129] 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 the third direction Y; between the first battery module 121 and the second battery module 122 in each group, they are all connected through the first transition connecting piece 123, the second transition connecting piece 124, and the conduction connecting piece 125. Between adjacent battery modules 120, they are all connected by the first transition connecting piece 123, the second transition connecting piece 124, and the conduction connecting piece 125, which can further improve the safety performance of the battery pack 100.

[0130] In the embodiments of the present disclosure, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance; the term "multiple" means two or more, unless otherwise clearly defined. Terms such as "installation", "connection", "connection", and "fixation" should all be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; "connection" 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 specific circumstances.

[0131] In the description of the embodiments of the present disclosure, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings. It is 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. Therefore, it should not be construed as a limitation to the embodiments of the present disclosure.

[0132] In the description of the specification of the present disclosure, the description of terms such as "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or instance. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0133] After considering the specification and practicing the invention disclosed herein, those skilled in the art will readily conceive of other embodiments of the present disclosure. 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 known common general knowledge or conventional technical means in the technical field not disclosed in the present disclosure. The specification and examples are only to be considered as exemplary, and the true scope and spirit of the present disclosure are pointed out by the appended claims.

Claims

1. A battery pack, characterized in that, Comprising: A battery box body, in which a battery compartment is formed; A plurality of battery modules, which are located in the battery compartment; Each of the battery modules includes a plurality of battery cells arranged in a first direction and end plates clamped at both ends of the plurality of battery cells; the plurality of battery modules at least include a first battery module and a second battery module arranged adjacent to each other in the first direction. An insulated first output pole base is provided on the first end plate adjacent to the second battery module in the first battery module, and a first output pole connecting piece is provided on the battery cell adjacent to the first end plate; An insulated second output pole base is provided on the second end plate adjacent to the first battery module in the second battery module, and a second output pole connecting piece is provided on the battery cell adjacent to the second end plate; A first transition connecting piece and a second transition connecting piece, the first transition connecting piece is located on the first output pole base and is connected to the first output pole connecting piece, and the resistance of the first transition connecting piece is less than the resistance of the first output pole connecting piece; The second transition connecting piece is located on the second output pole base and is connected to the second output pole connecting piece, and the resistance of the second transition connecting piece is less than the resistance of the second output pole connecting piece; A conduction connecting piece, the conduction connecting piece includes a first end and a second end arranged opposite to each other in the first direction, the first end is connected to the first transition connecting piece, and the second end is connected to the second transition connecting piece.

2. The battery pack according to claim 1, characterized in that, The first output pole connecting piece and the first output pole base are spaced apart from each other in the first direction, and one end of the first transition connecting piece extends out of the first output pole base to be connected to the first output pole connecting piece; And / or, the second output pole connecting piece and the second output pole base are spaced apart from each other in the first direction, and one end of the second transition connecting piece extends out of the second output pole base to be connected to the second output pole connecting piece.

3. The battery pack according to claim 1, characterized in that, Along a second direction, the first output pole base is located on one side of the first end plate, and the second output pole base is located on one side of the second end plate; The first output pole connecting piece and the conduction connecting piece are located on opposite sides of the first transition connecting piece along the second direction, and / or, the second output pole connecting piece and the conduction connecting piece are located on opposite sides of the second transition connecting piece along the second direction.

4. The battery pack according to claim 1, characterized in that, A first avoidance notch is provided at one end of the first transition connecting piece facing the first output pole connecting piece in the first direction, and the first avoidance notch is used to avoid the part where the first output pole connecting piece is connected to the electrode of the battery cell; and / or, a second avoidance notch is provided at one end of the second transition connecting piece facing the second output pole connecting piece in the first direction, and the second avoidance notch is used to avoid the part where the second output pole connecting piece is connected to the electrode of the battery cell.

5. The battery pack according to claim 1, wherein, Along a second direction, the first output pole base is located on one side of the first end plate, and the second output pole base is located on one side of the second end plate; The first transition connecting piece includes a first connecting portion and a second connecting portion which are oppositely arranged along the first direction. The first connecting portion is connected to the first output pole connecting piece, and the second connecting portion is connected to the conducting connecting piece. Moreover, the second connecting portion sinks towards the side of the first end plate along the second direction relative to the first connecting portion; and / or, the second transition connecting piece includes a third connecting portion and a fourth connecting portion which are oppositely arranged along the first direction. The third connecting portion is connected to the second output pole connecting piece, and the fourth connecting portion is connected to the conducting connecting piece. Moreover, the fourth connecting portion sinks towards the side of the second end plate along the second direction relative to the third connecting portion.

6. The battery pack according to claim 1, characterized in that, The first transition connecting piece includes a first connecting portion and a second connecting portion which are oppositely arranged along the first direction. The first connecting portion is connected to the first output pole connecting piece, and the second connecting portion is connected to the conducting connecting piece; a first bending portion is further provided between the first connecting portion and the second connecting portion of the first transition connecting piece; and / or, the second transition connecting piece includes a third connecting portion and a fourth connecting portion which are oppositely arranged along the first direction. The third connecting portion is connected to the second output pole connecting piece, and the fourth connecting portion is connected to the conducting connecting piece; a second bending portion is further provided between the third connecting portion and the fourth connecting portion of the second transition connecting piece.

7. The battery pack according to claim 1, wherein, The conducting connecting piece includes a fifth connecting portion and a sixth connecting portion which are oppositely arranged along the first direction. The fifth connecting portion is connected to the first transition connecting piece, and the sixth connecting portion is connected to the second transition connecting piece; a third bending portion is further provided between the fifth connecting portion and the sixth connecting portion of the conducting connecting piece.

8. The battery pack according to claim 1, characterized in that, A first limiting groove is provided on the first output pole base, and the first transition connecting piece is located in the first limiting groove; along the third direction, the width of at least a part of the first output pole connecting piece is greater than the width of the first limiting groove; and / or, a second limiting groove is provided on the second output pole base, and the second transition connecting piece is located in the second limiting groove; along the third direction, the width of at least a part of the second output pole connecting piece is greater than the width of the second limiting groove; 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.

9. The battery pack according to claim 1, wherein, The first end of the conducting connecting piece and the first transition connecting piece are fixedly connected to the first output pole base through a threaded member, and / or the second end of the conducting connecting piece and the second transition connecting piece are fixedly connected to the second output pole base through a threaded member.

10. The battery pack according to claim 1, characterized in that, The first transition connecting piece is welded to the first output pole connecting piece, and / or, the second transition connecting piece is welded to the second output pole connecting piece.

11. The battery pack according to claim 1, wherein The first transition connection piece is provided with a first convex portion, the first output pole connection piece is provided with a first concave portion, and the first convex portion is located in the first concave portion; and / or, the second transition connection piece is provided with a second convex portion, the second output pole connection piece is provided with a second concave portion, and the second convex portion is located in the second concave portion.

12. The battery pack according to claim 1, wherein, The resistance of the first transition connection piece and / or the second transition connection piece is less than or equal to the resistance of the conduction connection piece.

13. The battery pack according to claim 1, characterized in that, The first transition connection piece and / or the second transition connection piece are made of the same material as the conduction connection piece.

14. The battery pack according to claim 1, wherein Along the second direction, the first output pole base is located on one side of the first end plate, and the second output pole base is located on one side of the second end plate. The first transition connection piece includes a first conductive layer and a second conductive layer along the second direction. The first conductive layer is located on the side facing the first output pole connection piece and is made of the same material as the first output pole connection piece. The second conductive layer is located on the side facing the conduction connection piece and is made of the same material as the conduction connection piece; and / or, the second transition connection piece includes a third conductive layer and a fourth conductive layer along the second direction. The third conductive layer is located on the side facing the second output pole connection piece and is made of the same material as the second output pole connection piece. The fourth conductive layer is located on the side facing the conduction connection piece and is made of the same material as the conduction connection piece.

15. The battery pack according to claim 1, wherein The plurality of 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 the third direction; between the first battery module and the second battery module in each group are connected through the first transition connection piece, the second transition connection piece and the conduction connection 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.

16. An energy storage system, characterized in that, Including the battery pack according to any one of claims 1 to 15.

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