Battery pack and energy storage system

Abstract

A battery pack and an energy storage system, which relate to the technical field of energy storage. The battery pack comprises: a battery case body, a plurality of battery modules, and a conductive connecting piece, wherein a battery compartment is formed in the battery case body; the plurality of battery modules are located in the battery compartment; the plurality of battery modules comprise a first battery module and a second battery module, the first battery module being internally provided with a first output terminal base and a first output terminal connecting piece, and the second battery module being internally provided with a second output terminal base and a second output terminal connecting piece; a first connecting portion of the conductive connecting piece is located on the first output terminal base and is connected to the first output terminal connecting piece, and a second connecting portion thereof is located on the second output terminal base and is connected to the second output terminal connecting piece; and an insulating layer is provided on a surface of an intermediate connecting portion, and the insulating layer overlaps with the first output terminal base and the second output terminal base.

Description

Battery pack and energy storage system

[0001] Cross-reference to Related Applications

[0002] The present disclosure claims priority to Chinese Patent Application No. 202411126819.2, filed on August 16, 2024, the disclosure of which is incorporated herein in its entirety as part of the present disclosure. TECHNICAL FIELD

[0003] The present disclosure relates to the technical field of energy storage, and in particular, to a battery pack and energy storage system. BACKGROUND

[0004] A plurality of battery modules are usually included in a battery pack, and electrical connection is usually required between the plurality of battery modules. When a connecting sheet is used to achieve electrical connection between the battery modules, there is a risk of short circuit between the connecting sheet and the end plate, as the end plate at both ends of the battery module is usually a metal end plate that needs to be insulated, which seriously affects the safety performance of the battery pack.

[0005] It should be noted that the information disclosed in the above background section is only used to strengthen the understanding of the background of the present disclosure, and therefore can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0006] The purpose of the present disclosure is to provide a battery pack and energy storage system.

[0007] According to one aspect of the present disclosure, a battery pack is provided, comprising:

[0008] a battery box body, the battery box body being formed with a battery compartment;

[0009] a plurality of battery modules, the plurality of battery modules being located in the battery compartment; each of the battery modules comprises a plurality of battery cells arranged along a first direction and end plates clamped at both ends of the plurality of battery cells; the plurality of battery modules at least comprises a first battery module and a second battery module arranged adjacent to each other along the first direction, a first output pole base insulated is provided on a first end plate adjacent to the second battery module in the first battery module, and a first output pole connecting sheet is provided on the battery cell adjacent to the first end plate; a second output pole base insulated is provided on a second end plate adjacent to the first battery module in the second battery module, and a second output pole connecting sheet is provided on the battery cell adjacent to the second end plate;

[0010] The conducting connecting piece includes a first connecting part, a second connecting part and an intermediate connecting part between the first connecting part and the second connecting part, the first connecting part is connected with the first output pole connecting piece on the first output pole base, and the second connecting part is connected with the second output pole connecting piece on the second output pole base.

[0011] The surface of the intermediate connecting part is provided with an insulating layer, and the insulating layer has an overlapping part with the first output pole base and the second output pole base in the first direction.

[0012] The battery pack provided by the present disclosure is provided with the conducting connecting piece, the two ends of the conducting connecting piece are respectively located on the first output pole base and the second output pole base, and insulation between the first end plate and the second end plate is realized; the surface of the intermediate connecting part is provided with an insulating layer, which can insulate the surface of the conducting connecting piece exposed between the first end plate and the second end plate, so that the creepage path between the conducting connecting piece, the first end plate and the second end plate needs to pass through the insulating layer to the output pole base side plate and then to the exposed first end plate and second end plate, thereby increasing the creepage distance between the originally electrified conducting connecting piece and the exposed surface of the first end plate and the second end plate, and improving the creepage short circuit phenomenon between the conducting connecting piece and the first end plate and the second end plate; meanwhile, the edge position of the insulating layer is moved inward to the inside of the first output pole base, so that in the case that the first battery module and the second battery module are stretched by the displacement of the conducting connecting piece due to expansion, the creepage distance between the conducting connecting piece and the first end plate and the second end plate is ensured to be within the insulation safety range to the greatest extent, and a safety accident caused by short circuit is avoided, thereby improving the safety performance of the battery pack.

[0013] According to another aspect of the present disclosure, a kind of energy storage system is provided, which includes the above battery pack.

[0014] 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 DRAWINGS

[0015] The drawings herein are incorporated into the specification and form part of the specification, show embodiments consistent with the present disclosure, and together with the specification, serve to explain the principles of the present disclosure. Obviously, the drawings in the following description are only some embodiments of the present disclosure, and other drawings can be obtained by those skilled in the art without creative labor.

[0016] Fig. 1 is a schematic diagram of an energy storage system according to an embodiment of the present disclosure.

[0017] Fig. 2 is a schematic diagram of a battery pack according to an embodiment of the present disclosure.

[0018] FIG. 3 is an exploded schematic view of a battery pack according to an embodiment of the present disclosure.

[0019] FIG. 4 is a schematic view of a battery module according to an embodiment of the present disclosure.

[0020] FIG. 5 is a schematic view of the electrical connection between a first battery module and a second battery module according to an embodiment of the present disclosure.

[0021] FIG. 6 is a partial enlarged view of A in FIG. 5.

[0022] FIG. 7 is a schematic view of the electrical connection between a first battery module and a second battery module after removing the base cover according to an embodiment of the present disclosure.

[0023] FIG. 8 is a partial enlarged view of B in FIG. 7.

[0024] FIG. 9 is a schematic view of the electrical connection between a first battery module and a second battery module after removing the base cover according to another embodiment of the present disclosure.

[0025] FIG. 10 is a partial enlarged view of C in FIG. 9.

[0026] FIG. 11 is a schematic view of the electrical connection structure between a first battery module and a second battery module according to an embodiment of the present disclosure.

[0027] FIG. 12 is a schematic view of a conductive connecting piece according to an embodiment of the present disclosure.

[0028] FIG. 13 is a schematic view of a first transition connecting piece and a second transition connecting piece according to an embodiment of the present disclosure.

[0029] FIG. 14 is a schematic view of a first transition connecting piece and a second transition connecting piece according to another embodiment of the present disclosure.

[0030] FIG. 15 is a schematic view of a first output pole base and a second output pole base according to an embodiment of the present disclosure.

[0031] FIG. 16 is a schematic view of a first output pole base and a second output pole base according to another embodiment of the present disclosure.

[0032] Explanation of Reference Signs: 10, energy storage device; 20, power grid; 30, first electric energy conversion device; 40, second electric energy conversion device; 100, battery pack; 110, battery box; 111, lower box; 112, box cover; 120, battery module; 121, first battery module; 1211, first battery cell; 1212, first end plate; 1213, first output pole base; 12131, first base; 12132, first protruding portion; 12133, first side plate; 12134, first extending portion; 12135, first extension; 12136, first reinforcing rib; 1214, first base cover plate; 1215, first output pole connecting piece; 1216, first cell connecting piece; 1217, first cable tie; 1218, first insulating plate; 122, second battery module; 1221, second battery cell; 1222, second end plate; 1223, second output pole base; 12231, second base; 12232, second protruding portion; 12233, second side plate; 12234, second extending portion; 12235, second extension; 12236, second reinforcing rib; 1224, second base cover plate; 1225, second output pole connecting piece; 1226, second cell connecting piece; 1227, second cable tie; 1228, second insulating plate; 123, first transition connecting piece; 1231, first end; 1232, second end; 1233, third connecting portion; 1234, fourth connecting portion; 1235, first bent portion; 1236, first avoiding notch; 1237, first conductive layer; 1238, second conductive layer; 1239, second via hole; 124, second transition connecting piece; 1241, first end; 1242, second end; 1243, fifth connecting portion; 1244, sixth connecting portion; 1245, second bent portion; 1246, second avoiding notch; 1247, third conductive layer; 1248, fourth conductive layer; 1249, fourth via hole; 125, through connecting piece; 1251, first end; 1252, second end; 1253, first connecting portion; 1254, second connecting portion; 1255, intermediate connecting portion; 1256, insulating layer; 1257, first via hole; 1258, third via hole; 1261, first screw; 1262, second screw; 1263, third screw; 1264, fourth screw. DETAILED DESCRIPTION

[0033] Example embodiments now will be described more fully hereinafter with reference to the accompanying drawings; however, the example embodiments can be implemented in many different forms and should not be construed as limited to the implementations set forth herein; rather, these implementations 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 refer to like elements throughout the figures, and description of these elements will not be repeated.

[0034] Since the energy required by people has strong time and space, in order to reasonably use energy and improve the utilization rate, it is necessary to store the energy in the form of one energy form or another energy form through a medium or device, and then release it in a specific energy form based on future application.

[0035] At present, green energy mainly includes light energy, wind energy, etc., and light energy and wind energy have the problems of strong intermittency and large fluctuation, which will cause the voltage instability of green power grid (not enough electricity at peak electricity consumption, and too much electricity at low electricity consumption), and unstable voltage will cause damage to electricity, Therefore, due to insufficient electricity demand or insufficient grid accommodation capacity, the problem of "abandoning wind and light" may occur.

[0036] In order to solve the problem of insufficient electricity demand or insufficient grid accommodation 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 through physical or chemical means for storage, and when needed, the energy stored in the energy storage device is converted into electrical energy and released. Simply put, the energy storage device is similar to a large "power bank", which stores electrical energy when light energy and wind energy are sufficient, and releases the stored electrical energy when needed.

[0037] The current energy storage (i.e. energy storage) application scenarios are relatively wide, including power generation side energy storage, power grid side energy storage, renewable energy grid-connected energy storage, and user side energy storage, etc. The corresponding types of energy storage devices include:

[0038] (1) Large-scale energy storage power station applied in wind power, photovoltaic power station and other power generation side energy storage scenarios, which can assist renewable energy power generation to meet grid connection requirements and improve renewable energy utilization rate; Energy storage power station as a high-quality active / reactive power regulation power source in the power supply side, realizes the load matching of electrical energy in time and space, enhances the renewable energy consumption capacity, reduces the instantaneous power change, reduces the impact on the power grid, improves the new energy power generation consumption problem, and has great significance in power grid system backup, relieving peak load power supply pressure and peak regulation;

[0039] (2) Large-scale energy storage container applied in power grid side energy storage scenarios, the main functions are peak regulation, frequency regulation, and relieving power grid congestion peak regulation, which can realize the peak clipping and valley filling of electricity load, that is, charging the energy storage battery when the electricity load is low, and releasing the stored electricity during the peak period of electricity load, so as to realize the balance between power production and consumption, such as energy storage power station system;

[0040] (3) Small and medium-sized energy storage cabinets applied in industrial and commercial energy storage scenarios (banks, shopping malls, etc.) on the user side and small household energy storage boxes applied in household energy storage scenarios on the user side, the functions of which mainly include power self-generation and self-use, peak load shifting, capacity cost management, and improvement of power supply reliability. According to different application scenarios, the power consumption side energy storage 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 photovoltaic power. Since there is a large price difference in electricity bills at peak and valley positions according to power consumption demand, after users have energy storage devices, in order to reduce costs, the energy storage devices (energy storage cabinets / boxes) are usually charged at low electricity prices. At the peak of electricity prices, the electricity in the energy storage devices is discharged for use, in order to achieve the purpose of saving electricity bills. In addition, communication base stations, data centers, and other fields need to be equipped with energy storage for backup power. In addition, 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 the user providing backup power for himself and the power grid, eliminating the inconvenience caused by frequent power outages due to disasters or other reasons.

[0041] FIG. 1 is a schematic diagram of an energy storage system according to an embodiment of the present disclosure, and the embodiment of the present disclosure takes the power generation / distribution side shared energy storage scenario as an example for illustration. The energy storage system of the present disclosure is not limited to the power generation / distribution side energy storage scenario, but can also be applied to industrial and commercial side or user side scenarios, etc.

[0042] As shown in FIG. 1, the energy storage system includes an energy storage device 10, a power grid 20, a first electric energy conversion device 30, and a second electric energy conversion device 40. In the case of power generation, the first electric energy conversion device 30 and the second electric energy conversion device 40 are used to convert other forms of energy into electric energy, which is connected to the power grid 20 for use by the power consumption side of the distribution network. When the power consumption load is low, the first electric energy conversion device 30 and the second electric energy conversion device 40 generate excess electricity, which is stored in the energy storage device 10, reducing the rate of abandoned wind and light, and improving the problem of new energy power generation consumption. When the power consumption load is high, the power grid issues an instruction to transmit the electricity stored in the energy storage device 10 in cooperation with the power grid 20 in a grid-connected mode to supply the power consumption side, providing peak shaving, frequency modulation, backup, and other services for the operation of the power grid 20, fully utilizing the peak shaving function of the power grid 20, promoting the peak shaving of the power grid 20, and relieving the power supply pressure of the power grid 20.

[0043] Among them, the first electric energy conversion device 30 can be a solar energy conversion device, and the second electric energy conversion device 40 can be a wind energy conversion device. Of course, the electric energy conversion device can also be a device that converts at least one of thermal energy, tidal energy, biomass energy, and mechanical energy into electric energy.

[0044] In combination with the above 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, which uses chemical elements in the chemical battery as an energy storage medium to achieve the charging and discharging process through chemical reactions or changes of the energy storage medium. In simple terms, the electrical energy generated by light energy and wind energy is stored in at least one set of chemical batteries through chemical reactions or changes of the energy storage medium. When the use of external electrical energy reaches a peak, the electrical energy stored in the at least one set of chemical batteries is released and used through chemical reactions or changes of the energy storage medium, or transferred to places where electrical energy is in short supply for use.

[0045] The energy storage device 10 can be a battery pack composed of battery monomers, an energy storage box, an energy storage cabinet, etc. The battery monomers can be lithium ion secondary batteries, lithium-sulfur batteries, sodium lithium ion batteries, sodium ion batteries, magnesium ion batteries, etc., and the battery monomers can be in the form of a cylinder, a flat body, a cuboid, etc., which is not limited in the embodiments of the present application.

[0046] As shown in FIGS. 2-4, taking the energy storage device 10 as an example of a battery pack 100, the battery pack 100 includes a battery box 110 and a plurality of battery modules 120. The battery box 110 includes a lower box 111 and a box cover 112, and the box cover 112 is fixedly / detachably connected with the lower box 111 to enclose a battery compartment. The plurality of battery modules 120 are located in the battery compartment.

[0047] The battery modules 120 accommodated in the battery compartment of the battery box 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, thereby more easily meeting market demand. For example, as shown in FIG. 3, the battery compartment of the battery box 110 accommodates two rows along the length direction of the battery box 110 and four columns along the width direction of the battery box 110, totaling eight battery modules 120.

[0048] The battery module 120 can include a pair of end plates arranged opposite to each other along the direction of the 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 a binding tool such as a cable tie. The plurality of battery cells are arranged along the length direction of the battery box 110, and the plurality of battery cells are connected by the battery cell connecting piece to realize the series / parallel electrical connection between the plurality of battery cells. For example, as shown in FIG. 5, the first battery module 121 includes a pair of first end plates 1212 arranged opposite to each other, and a plurality of first battery cells 1211 located between the pair of first end plates 1212. The plurality of first battery cells 1211 and the pair of first end plates 1212 are 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 battery cell connecting piece 1216 to realize the series / parallel electrical connection between the plurality of first battery cells 1211. The second battery module 122 includes a pair of second end plates 1222 arranged opposite to each other, and a plurality of second battery cells 1221 located between the pair of second end plates 1222. The plurality of second battery cells 1221 and the pair of second end plates 1222 are 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 battery cell connecting piece 1226 to realize the series / parallel electrical connection between the plurality of second battery cells 1221.

[0049] The plurality of battery cells are connected in series, and each battery cell connecting piece is connected to the electrode terminals of two battery cells with different polarities. Alternatively, two battery cells are connected in parallel to form a group, and the groups are connected in series. In this case, each battery cell connecting piece is connected to the electrode terminals of two battery cells with the same polarity, and then connected to the electrode terminals of other two battery cells with opposite polarities.

[0050] The outer wall of each battery cell can be covered with an insulating film to avoid safety hazards caused by shell leakage. As shown in FIGS. 5 and 6, the first battery module 121 includes a first insulating plate 1218 located between the first end plate 1212 and the first battery cell 1211 adjacent to the first end plate 1212. The first insulating plate 1218 can prevent the first end plate 1212 from piercing the insulating film on the first battery cell 1211 due to burrs or protruding structures on the first end plate 1212. In addition, the first battery cell 1211 is charged, and the first end plate 1212 is not charged. The first insulating plate 1218 can increase the creepage distance between the first battery cell 1211 and the first end plate 1212, ensure that the first end plate 1212 is not charged, and avoid the battery box 110 being charged, thereby improving the safety of the operator.

[0051] The second battery module 122 comprises a second insulating plate 1228 between the second end plate 1222 and the second battery cell 1221 adjacent to the second end plate 1222, so as to avoid that the burr or protruding structure on the second end plate 1222 pierces the insulating film on the second battery cell 1221, and avoid that the second battery cell 1221 causes the second end plate 1222 to be electrified after leakage; meanwhile, since the second battery cell 1221 is electrified and the second end plate 1222 is not electrified, the second insulating plate 1228 can increase the creepage distance between the second battery cell 1221 and the second end plate 1222, ensure that the second end plate 1222 is not electrified, and thus avoid that the battery box 110 is electrified, and improve the safety of the operation of the staff.

[0052] In the related art, since the copper bars between the battery modules 120 span the end plates of two battery modules 120, and the two ends are respectively located on the output pole bases on the end plates, a part of the copper bars is suspended between the two end plates; at this time, the electrified copper bars located in the middle suspended position are too close to the two end plates, and the creepage short circuit may occur; when the dust or electrified particles in the air around the output pole base exist, the creepage distance between the copper bars and the end plates is further reduced, and the creepage phenomenon occurs between the two, which finally causes the end plate to be electrified, and seriously threatens the safety of the battery pack 100.

[0053] To solve the above technical problems, the embodiments of the present disclosure provide a battery pack 100, as shown in FIGS. 2-12, which comprises a battery box 110, a plurality of battery modules 120 and a conductive connecting piece 125. The battery box 110 is formed with a battery compartment, and the plurality of battery modules 120 are located in the battery compartment; each battery module 120 comprises a plurality of battery cells arranged along a first direction X and an end plate clamped at both ends of the plurality of battery cells, and the first direction X can be the length direction of the battery pack 100; the plurality of battery modules 120 at least comprise a first battery module 121 and a second battery module 122 arranged adjacent along the first direction X; hereinafter, the present disclosure takes the first battery module 121 and the second battery module 122 as examples to discuss the electrical connection structure between the adjacent battery modules 120 in detail.

[0054] The first end plate 1212 adjacent to the second battery module 122 in the first battery module 121 is provided with an insulating first output pole base 1213, and the battery cell adjacent to the first end plate 1212 is provided with a first output pole connecting piece 1215; the second end plate 1222 adjacent to the first battery module 121 in the second battery module 122 is provided with an insulating second output pole base 1223, and the battery cell adjacent to the second end plate 1222 is provided with a second output pole connecting piece 1225.

[0055] The conduction connecting piece 125 includes a first connecting part 1253, a second connecting part 1254 and an intermediate connecting part 1255 located between the first connecting part 1253 and the second connecting part 1254, which are oppositely arranged along the first direction X. The first connecting part 1253 is connected with the first output pole connecting piece 1215, and the second connecting part 1254 is connected with the second output pole connecting piece 1225. In the first direction X, the intermediate connecting part 1255 has overlapping parts with the first output pole base 1213 and the second output pole base 1223. An insulating layer 1256 is arranged on the surface of the intermediate connecting part 1255, and the insulating layer 1256 has overlapping parts with the first output pole base 1213 and the second output pole base 1223.

[0056] The battery pack 100 provided by the present disclosure is characterized in that the two ends of the conduction connecting piece 125 are located on the first output pole base 1213 and the second output pole base 1223 respectively, thereby realizing insulation between the first end plate 1212 and the second end plate 1222. Meanwhile, the intermediate connecting part 1255 of the conduction connecting piece 125 is located between the first end plate 1212 and the second end plate 1222, and the insulating layer 1256 is arranged on the surface of the intermediate connecting part 1255, thereby insulating the surface of the conduction connecting piece 125 exposed between the first end plate 1212 and the second end plate 1222. Due to the close distance between the suspended charged conduction connecting piece 125 and the first end plate 1212 and the second end plate 1222 at both ends, the shortest path between the charged conduction connecting piece 125 and the first end plate 1212 and the second end plate 1222 at both ends may appear a creeping phenomenon when the conduction connecting piece 125 is exposed. When the conduction connecting piece 125 is not provided with the insulating layer 1256, the creeping distance is the shortest path on the surface of the first end plate 1212 and the second end plate 1222 reached by the intermediate connecting part 1255 of the conduction connecting piece 125 across the bottom surface height of the first output pole connecting piece 1215 and the second output pole base 1223. When the conduction connecting piece 125 is provided with the insulating layer 1256, the creeping path between the conduction connecting piece 125 and the first end plate 1212 and the second end plate 1222 needs to pass through the insulating layer 1256 and then reach the exposed first end plate 1212 and the second end plate 1222, thereby increasing the creeping distance between the charged conduction connecting piece 125 and the exposed surface of the first end plate 1212 and the second end plate 1222, and improving the creeping short circuit phenomenon between the conduction connecting piece 125 and the first end plate 1212 and the second end plate 1222, and improving the safety performance of the battery pack 100.

[0057] In addition, under normal working conditions of the battery cell, the expansion of the battery cell will cause displacement of the entire battery module 120. In this case, the spacing between the first battery module 121 and the second battery module 122 will change due to the displacement, and the conduction connecting piece 125 will be affected by stretching. The original position of the conduction connecting piece 125 covered by the insulating layer 1256 will be exposed due to stretching, the exposed area of the conduction connecting piece 125 will increase and be exposed from the gap between the first end plate 1212 and the second end plate 1222, which will reduce the creepage distance of the conduction connecting piece 125 and the exposed surfaces of the first end plate 1212 and the second end plate 1222, and thus easily cause a creepage short circuit phenomenon. Therefore, the edge position of the insulating layer 1256 is moved inward to the inside of the first output pole base 1213 and the second output pole base 1223. In the case of stretching of the conduction connecting piece 125 due to expansion displacement of the first battery module 121 and the second battery module 122, the creepage distance between the conduction connecting piece 125 and the first end plate 1212 and the second end plate 1222 is guaranteed to be within the insulating safety range to the greatest extent, avoiding short circuit and causing safety accidents.

[0058] In one embodiment, the insulating layer 1256 is made of an elastic material. By using an elastic material for the insulating layer 1256, when the conduction connecting piece 125 is a non-planar structure, such as a bending structure, the elastic material of the insulating layer 1256 can better adhere to the surface of the conduction connecting piece 125 to improve the insulation performance of the conduction connecting piece 125.

[0059] The insulating layer 1256 is bonded to the conduction connecting piece 125. The insulating layer 1256 is fixedly connected to the conduction connecting piece 125 by bonding, which facilitates the setting of the insulating layer 1256 on the conduction connecting piece 125, and facilitates the bonding and covering of the part of the conduction connecting piece 125 that needs to be insulated according to actual needs. In addition, when the insulating layer 1256 is damaged and fails, it is convenient to tear off and replace the insulating layer 1256.

[0060] The insulating layer 1256 is an insulating tape. The use of an insulating tape facilitates the setting of the insulating layer 1256 on the conduction connecting piece 125. The insulating tape has good elasticity and can be tightly adhered to the surface of the conduction connecting piece 125 by bonding. The insulating tape can be wound multiple times on the part of the conduction connecting piece 125 that needs to be insulated, improving the insulation effect and preventing the insulating layer 1256 from being easily pierced when it is relatively thin.

[0061] Of course, the insulating layer 1256 can also be formed by spraying or injection molding process, and the present disclosure does not limit this. Any insulating layer 1256 and method of setting the insulating layer 1256 that can achieve insulation effect belongs to the protection scope of the present disclosure.

[0062] In one embodiment, the surface of the intermediate connecting part 1255 is provided with an insulating layer 1256. The insulating layer 1256 can be provided on the overhanging part of the conduction connecting piece 125, the part overlapping the first output pole connecting piece 1215 and the second output pole base 1223, or the part of the conduction connecting piece 125 not in contact with other conductive parts, to further improve the insulation of the exposed part of the conduction connecting piece 125, thereby further improving the creepage short circuit phenomenon between the conduction connecting piece 125 and the first end plate 1212 and the second end plate 1222, and further improving the safety performance of the battery pack 100.

[0063] Specifically, as shown in FIG. 12, the first battery module 121 and the second battery module 122 have a preset gap therebetween in the first direction X, and the intermediate connecting part 1255 is arranged corresponding to the preset gap. By providing the insulating layer 1256 on the intermediate connecting part 1255, the surface of the conduction connecting piece 125 exposed in the preset gap can be insulated.

[0064] In one embodiment, at least part of the intermediate connecting part 1255 is in a bent structure, and the bent structure can enable the first connecting part 1253 and the second connecting part 1254 to move away from or towards each other in the first direction X. Since the battery cell expands after long-term use, the conduction connecting piece 125 will be subjected to a stretching force from the first battery module 121 and the second battery module 122, which will cause the conduction connecting piece 125 to be stretched in the second direction Z, and thus easily deformed or even broken. By providing the bent structure, when the conduction connecting piece 125 is subjected to a stretching force, the bent structure can absorb the stretching force, thereby avoiding the conduction connecting piece 125 from being broken. Of course, the conduction connecting piece 125 can also not be provided with the bent structure, which is not limited in the present disclosure.

[0065] When the intermediate connecting part 1255 is provided with the bent structure, the part of the conduction connecting piece 125 between the first end plate 1212 and the second end plate 1222 should still be covered by the insulating layer 1256 when the conduction connecting piece 125 is in the maximum stretching state.

[0066] The insulating layer 1256 is made of elastic material. When the first connecting part 1253 and the second connecting part 1254 move away from or towards each other along the first direction X, the elastic insulating layer 1256 can stretch or contract to avoid the first connecting part 1253 and the second connecting part 1254 moving away from each other along the first direction X to stretch the through-connection piece 125, so that the part originally covered by the insulating layer 1256 is exposed due to stretching, thereby improving the insulation effect of the through-connection piece 125. At the same time, by setting the elastic insulating layer 1256, in the case that the first battery module 121 and the second battery module 122 expand and displace the through-connection piece 125, the overlapping part between the insulating layer 1256 and the first output terminal connecting piece 1215 and the second output terminal base 1223 can be ensured to the maximum, that is, the creepage distance between the through-connection piece 125 and the first end plate 1212 and the second end plate 1222 is ensured to be within the insulation safety range, thereby avoiding short circuit and safety accidents.

[0067] The insulating layer 1256 can be set to have sufficient overlapping length with the first output terminal connecting piece 1215 and the second output terminal base 1223 along the first direction X. When the first connecting part 1253 and the second connecting part 1254 move away from each other along the first direction X, the intermediate connecting part 1255 in the flat state has overlapping part with the first output terminal connecting piece 1215 and the second output terminal base 1223 along the first direction X, thereby ensuring the creepage distance between the through-connection piece 125 and the first end plate 1212 and the second end plate 1222 to be within the insulation safety range, thereby avoiding short circuit and safety accidents.

[0068] Of course, when the intermediate connecting part 1255 is not provided with the bending structure, the above-mentioned elastic insulating layer 1256 and the insulating layer 1256 with sufficient length can also be used to ensure that the part of the through-connection piece 125 between the first end plate 1212 and the second end plate 1222 can be covered by the insulating layer 1256 in the maximum stretching state.

[0069] In one embodiment, as shown in FIGS. 7, 8 and 15, the first output pole base 1213 is arranged on one side of the first end plate 1212 along the second direction Z, and first side plates 12133 extending towards the second direction Z are arranged on both sides of the first output pole base 1213 along the third direction Y; in the second direction Z, the height of the first side plates 12133 is greater than the thickness of the first connecting part 1253. Since the electrified conducting connecting piece 125 is spaced from the surface of the first end plate 1212 directly below the first output pole base 1213 by the first base 12131 of the first output pole base 1213, the dielectric constant of the first base 12131 is large and no creepage phenomenon occurs; therefore, the creepage between the electrified conducting connecting piece 125 and the first end plate 1212 is through the position of the first side plates 12133 of the first output pole base 1213, and the creepage specifically occurs between the electrified conducting connecting piece 125 and the exposed surface of the first end plate 1212 closest to it. By increasing the height of the first side plates 12133, the creepage distance between the conducting connecting piece 125 in the first output pole base 1213 and the first end plate 1212 directly below it can be increased, so that when there are suspended dust or electrified particles and other pollutants in the air around the first output pole base 1213 during use of the battery pack 100, the creepage distance between the conducting connecting piece 125 and the first end plate 1212 is reduced, which can cause the creepage phenomenon between them, and further cause the safety accident of electrification of the first end plate 1212.

[0070] In one embodiment, as shown in FIGS. 7, 8 and 15, the first output pole base 1213 is arranged on one side of the first end plate 1212 along the second direction Z, and first side plates 12133 extending towards the second direction Z are arranged on both sides of the first output pole base 1213 along the third direction Y; in the second direction Z, the height of the first side plates 12133 is greater than the thickness of the first connecting part 1253. Since the electrified conducting connecting piece 125 is spaced from the surface of the first end plate 1212 directly below the first output pole base 1213 by the first base 12131 of the first output pole base 1213, the dielectric constant of the first base 12131 is large and no creepage phenomenon occurs; therefore, the creepage between the electrified conducting connecting piece 125 and the first end plate 1212 is through the position of the first side plates 12133 of the first output pole base 1213, and the creepage specifically occurs between the electrified conducting connecting piece 125 and the exposed surface of the first end plate 1212 closest to it. By increasing the height of the first side plates 12133, the creepage distance between the conducting connecting piece 125 in the first output pole base 1213 and the first end plate 1212 directly below it can be increased, so that when there are suspended dust or electrified particles and other pollutants in the air around the first output pole base 1213 during use of the battery pack 100, the creepage distance between the conducting connecting piece 125 and the first end plate 1212 is reduced, which can cause the creepage phenomenon between them, and further cause the safety accident of electrification of the first end plate 1212.

[0071] In one embodiment, as shown in FIGS. 7, 8 and 15, when the first output pole base 1213 is provided with a first side plate 12133, the first side plate 12133 is provided with a first protruding portion 12134 extending towards the side of the second end plate 1222 in the first direction X, and the first protruding portion 12134 protrudes from the first end plate 1212 in the first direction X. Since the conductive connecting piece 125 between the first battery module 121 and the second battery module 122 spans the first end plate 1212 and the second end plate 1222, and the two ends are respectively located on the first output pole base 1213 and the second output pole base 1223, the conductive connecting piece 125 has a part suspended between the first end plate 1212 and the second end plate 1222; at this time, the distance between the conductive connecting piece 125 suspended in the middle and the two end plates is too close, and the creeping electric short circuit may occur, the creeping electric between the exposed live conductive connecting piece 125 and the first end plate 1212 and the second end plate 1222 passes through the positions of the first side plate 12133 and the second side plate 12233. Through the first protruding portion 12134 on the first side plate 12133, it extends to the outside of the first end plate 1212, increases the distance between the live conductive connecting piece 125 and the first end plate 1212, so that the battery cell can better ensure the insulation between the first end plate 1212 and the live conductive connecting piece 125 in the working condition and the non-working condition, and prevent short circuit between them.

[0072] As shown in FIGS. 9, 10 and 15, when the second output pole base 1223 is provided with a second side plate 12233, the second side plate 12233 is provided with a second protruding portion 12234 extending towards the side of the first end plate 1212 in the second direction Z, and the second protruding portion 12234 protrudes from the second end plate 1222 in the first direction X. Through the second protruding portion 12234 on the second side plate 12233, it extends to the outside of the second end plate 1222, increases the distance between the live conductive connecting piece 125 and the second end plate 1222, so that the battery cell can better ensure the insulation between the first end plate 1212 and the live conductive connecting piece 125 in the working condition and the non-working condition, and prevent short circuit between them.

[0073] In one embodiment, as shown in FIGS. 7, 8 and 15, the first output pole base 1213 includes a first base 12131 between the first connecting portion 1253 and the first end plate 1212, and the first base 12131 is provided with a first protruding portion 12132 extending to the side of the second end plate 1222 in the first direction X, and the first protruding portion 12132 protrudes beyond the first end plate 1212 in the first direction X. By providing the first protruding portion 12132 on the first base 12131, the first protruding portion 12132 protrudes to the position of the top end outside the first end plate 1212, so that the creepage path between the live through-connection tab 125 and the exposed first end plate 1212 is the live through-connection tab 125-insulating layer 1256-first protruding portion 12132-first end plate 1212, which increases the distance between the through-connection tab 125 and the exposed first end plate 1212, so that the battery cell can better ensure the insulation between the first end plate 1212 and the live through-connection tab 125 in both working and non-working conditions, preventing short circuit between the two.

[0074] In one embodiment, as shown in FIGS. 7, 8 and 15, the first output pole base 1213 includes a first base 12131 between the first connecting portion 1253 and the first end plate 1212, and the first base 12131 is provided with a first protruding portion 12132 extending to the side of the second end plate 1222 in the first direction X, and the first protruding portion 12132 protrudes beyond the first end plate 1212 in the first direction X. By providing the first protruding portion 12132 on the first base 12131, the first protruding portion 12132 protrudes to the position of the top end outside the first end plate 1212, so that the creepage path between the live through-connection tab 125 and the exposed first end plate 1212 is the live through-connection tab 125-insulating layer 1256-first protruding portion 12132-first end plate 1212, which increases the distance between the through-connection tab 125 and the exposed first end plate 1212, so that the battery cell can better ensure the insulation between the first end plate 1212 and the live through-connection tab 125 in both working and non-working conditions, preventing short circuit between the two.

[0075] Wherein, as shown in FIG. 15, the first protruding part 12134 on the first side plate 12133 of the first output pole base 1213 is flushable with the first protruding part 12132 on the first base 12131 outside the first end plate 1212 to improve the structural strength of the outer edge of the first protruding part 12134 and the first protruding part 12132; the second protruding part 12234 on the second side plate 12233 of the second output pole base 1223 is flushable with the second protruding part 12232 on the second base 12231 outside the second end plate 1222 to improve the structural strength of the outer edge of the second protruding part 12234 and the second protruding part 12232.

[0076] In one embodiment, as shown in FIGS. 7, 8 and 15, the first output pole base 1213 is arranged on one side of the first end plate 1212 along the second direction Z, and the first output pole base 1213 is provided with a first extending part 12135 extending towards the side of the first end plate 1212, and the first extending part 12135 has an overlapping part with the first end plate 1212 in the second direction Z. The distance between the through-connection piece 125 located in the middle suspension position and the two end plates is too close, and the creeping electric short circuit may occur. The creeping electric between the exposed charged through-connection piece 125 and the first end plate 1212 and the second end plate 1222 passes through the positions of the first side plate 12133 and the second side plate 12233. The first extending part 12135 blocks the part of the through-connection piece 125 directly below the first end plate 1212 closest to the first end plate 1212, i.e. increases the distance between the charged through-connection piece 125 and the first end plate 1212, so that the insulation between the first end plate 1212 and the charged through-connection piece 125 can be better ensured in the working condition and the non-working condition, and the short circuit between the two is prevented.

[0077] Wherein, as shown in FIG. 9, 10 and 15, the second output pole base 1223 is arranged on one side of the second end plate 1222 along the second direction Z, and the second output pole base 1223 is provided with a second extending part 12235 extending towards the side of the second end plate 1222, and the second extending part 12235 has an overlapping part with the second end plate 1222 in the second direction Z. The second extending part 12235 blocks the part of the through-connection piece 125 directly below the second end plate 1222 closest to the second end plate 1222, i.e. increases the distance between the charged through-connection piece 125 and the second end plate 1222, so that the insulation between the second end plate 1222 and the charged through-connection piece 125 can be better ensured in the working condition and the non-working condition, and the short circuit between the two is prevented.

[0078] As shown in FIG. 16, the first reinforcing rib 12136 is arranged between the first protruding part 12132 on the first base 12131 and the first extending part 12135. Since the first extending part 12135 extends in a plate shape toward the first end plate 1212, the structural strength of the first extending part 12135 is improved by arranging the first reinforcing rib 12136, so that the first extending part 12135 is prevented from being deformed or broken under stress.

[0079] As shown in FIG. 16, the second reinforcing rib 12236 is arranged between the second protruding part 12232 on the second base 12231 and the second extending part 12235. Since the second extending part 12235 extends in a plate shape toward the second end plate 1222, the structural strength of the second extending part 12235 is improved by arranging the second reinforcing rib 12236, so that the second extending part 12235 is prevented from being deformed or broken under stress.

[0080] In one embodiment, as shown in FIGS. 5-13, the battery pack 100 further comprises a first transition connecting piece 123 and a second transition connecting piece 124. The first transition connecting piece 123 is arranged on the first output pole base 1213 and connected with the first output pole connecting piece 1215, and the resistance of the first transition connecting piece 123 is smaller than that of the first output pole connecting piece 1215. The second transition connecting piece 124 is arranged on the second output pole base 1223 and connected with the second output pole connecting piece 1225, and the resistance of the second transition connecting piece 124 is smaller than that of the second output pole connecting piece 1225. The conducting connecting piece 125 comprises a first end 1251 and a second end 1252 arranged oppositely, the first end 1251 is connected with the first transition connecting piece 123, and the second end 1252 is connected with the second transition connecting piece 124.

[0081] The battery pack 100 provided in the embodiment has the first transition connecting piece 123 arranged on the first output pole base 1213 and the second transition connecting piece 124 arranged on the second output pole base 1223. The first end 1251 of the conducting connecting piece 125 is connected with the first output pole connecting piece 1215 through the first transition connecting piece 123, and the second end 1252 of the conducting connecting piece 125 is connected 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 smaller than that of the first output pole connecting piece 1215, and the resistance of the second transition connecting piece 124 is smaller than that of the second output pole connecting piece 1225, the overcurrent capacity of the corresponding electrical connecting pieces on the first output pole base 1213 and the second output pole base 1223 is improved, so that the problem that the first output pole connecting piece 1215 arranged on the first output pole base 1213 and the second output pole connecting piece 1225 arranged on the second output pole base 1223 have relatively low overcurrent capacity after being narrowed, and the output pole connecting piece is easily heated seriously and broken, resulting in electrical connection failure, is avoided.

[0082] Wherein, when the first transition connecting piece 123 is arranged on the first output pole base 1213, the first end 1251 of the conducting connecting piece 125 can be located on the first transition connecting piece 123; at this time, the height of the first side plate 12133 is greater than the thickness sum of the first transition connecting piece 123 and the conducting connecting piece 125.

[0083] Wherein, when the second transition connecting piece 124 is arranged on the second output pole base 1223, the second end 1252 of the conducting connecting piece 125 can be located on the second transition connecting piece 124; at this time, the height of the second side plate 12233 is greater than the thickness sum of the second transition connecting piece 124 and the conducting connecting piece 125.

[0084] Specifically, the first output pole base 1213 is provided with a first limiting groove, and the first transition connecting piece 123 is located in the first limiting groove; along the third direction Y, the width of at least part of the first output pole connecting piece 1215 is greater than the width of the first limiting groove, that is, the width of the first output pole base 1213 is 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 to a shape with different widths, that is, the width of one end of the first output pole connecting piece 1215 close to the first output pole base 1213 is reduced to be narrow to be placed on the first output pole base 1213; by arranging the first transition connecting piece 123, it is connected with the conducting connecting piece 125 on the first output pole base 1213 instead of the first output pole connecting piece 1215.

[0085] Wherein, the second output pole base 1223 is provided with a second limiting groove, and the second transition connecting piece 124 is located in the second limiting groove; along the third direction Y, the width of at least part of the second output pole connecting piece 1225 is greater than the width of the second limiting groove, that is, the width of the second output pole base 1223 is 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 to a shape with different widths, that is, the width of one end of the second output pole connecting piece 1225 close to the second output pole base 1223 is reduced to be narrow to be placed on the second output pole base 1223; by arranging the second transition connecting piece 124, it is connected with the conducting connecting piece 125 on the second output pole base 1223 instead of the second output pole connecting piece 1225.

[0086] Specifically, the first output pole connecting piece 1215 is arranged in the first direction X apart from the first output pole base 1213, the first transition connecting piece 123 includes oppositely arranged first and second ends 1231 and 1232, and the first end 1231 of the first transition connecting piece 123 extends out of the first output pole base 1213 to connect with the first output pole connecting piece 1215.

[0087] When the first limiting groove formed by the first output pole base 1213 is of an equal-width structure, the first end 1231 of the first transition connecting piece 123 extends out of the first output pole base 1213 to connect with the first output pole connecting piece 1215, so that the first output pole connecting piece 1215 is prevented from being narrowed at one end close to the first output pole base 1213, and the first output pole connecting piece 1215 has sufficient width, thereby ensuring the overcurrent capacity of the first output pole connecting piece 1215 and avoiding the situation of heating or even melting. When the first limiting groove formed by the first output pole base 1213 is of a non-equal-width structure, for example, the width of the first output pole connecting piece 1215 at one end is relatively large, the first output pole connecting piece 1215 can also be connected with the first transition connecting piece 123 by being partially arranged on the first output pole base 1213 with a relatively large width, and in this case, the first end 1231 of the first transition connecting piece 123 does not need to extend out of the first output pole base 1213, and the width of the first output pole connecting piece 1215 is not affected, so that the overcurrent capacity of the first output pole connecting piece 1215 is reduced.

[0088] Specifically, the second output pole connecting piece 1225 is arranged in the first direction X apart from the second output pole base 1223, the second transition connecting piece 124 includes oppositely arranged first and second ends 1241 and 1242, and 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.

[0089] When the second limiting groove formed by the second output pole base 1223 is of an equal-width structure, the first end 1241 of the second transition connecting piece 124 is extended out of the second output pole base 1223 to be connected with the second output pole connecting piece 1225, so that the second output pole connecting piece 1225 is not narrowed at one end close to the second output pole base 1223, and has sufficient width, thereby ensuring the overcurrent capacity of the second output pole connecting piece 1225 and avoiding the situation of heating or even melting. When the second limiting groove formed by the second output pole base 1223 is of a non-equal-width structure, for example, the width of the second output pole connecting piece 1225 at one end close to the second output pole base 1223 is relatively large, the second output pole connecting piece 1225 can also be connected with the second transition connecting piece 124 by being partially located on the second output pole base 1223 with relatively large width. In this case, the first end 1241 of the second transition connecting piece 124 does not need to be extended out of the second output pole base 1223, and the width of the second output pole connecting piece 1225 is not affected, so that the overcurrent capacity of the second output pole connecting piece 1225 is reduced.

[0090] As shown in FIGS. 7-10, the first output pole connecting piece 1215 and the conduction connecting piece 125 are located on opposite sides of the first transition connecting piece 123 along the second direction Z. By locating the first output pole connecting piece 1215 and the conduction connecting piece 125 on opposite sides of the first transition connecting piece 123 along the second direction Z, that is, when the first transition connecting piece 123 is arranged, the first output pole connecting piece 1215, the first transition connecting piece 123 and the conduction connecting piece 125 can be arranged in a stacked manner in the thickness direction, thereby facilitating the connection between the first output pole connecting piece 1215, the first transition connecting piece 123 and the conduction connecting piece 125. Of course, the first output pole connecting piece 1215 and the conduction connecting piece 125 can also be located on the same side of the first transition connecting piece 123 along the second direction Z, which is not limited in the present disclosure.

[0091] The second output pole connecting piece 1225 and the conduction connecting piece 125 are located on opposite sides of the second transition connecting piece 124 along the second direction Z. By locating the second output pole connecting piece 1225 and the conduction connecting piece 125 on opposite sides of the second transition connecting piece 124 along the second direction Z, that is, when the second transition connecting piece 124 is arranged, the second output pole connecting piece 1225, the second transition connecting piece 124 and the conduction connecting piece 125 can be arranged in a stacked manner in the thickness direction, thereby facilitating the connection between the second output pole connecting piece 1225, the second transition connecting piece 124 and the conduction connecting piece 125. Of course, the second output pole connecting piece 1225 and the conduction connecting piece 125 can also be located on the same side of the second transition connecting piece 124 along the second direction Z, which is not limited in the present disclosure.

[0092] In one embodiment, as shown in FIG. 13, the first transition connecting piece 123 includes oppositely arranged third connecting portion 1233 and fourth connecting portion 1234 in the first direction X, the third connecting portion 1233 is connected with the first output pole connecting piece 1215, the fourth connecting portion 1234 is connected with the conduction connecting piece 125, and the fourth connecting portion 1234 is sunken toward the side of the first end plate 1212 relative to the third connecting portion 1233 in the second direction Z. By sinking the fourth connecting portion 1234 on the first transition connecting piece 123 relative to the third connecting portion 1233 in the second direction Z toward the side of the first end plate 1212, when the first transition connecting piece 123 is connected with the conduction connecting piece 125, the first connecting portion 1253 of the conduction connecting piece 125 connected with the first transition connecting piece 123 is located on the sunken fourth connecting portion 1234, which reduces the height of the first connecting portion 1253. Due to the displacement of the battery cell expansion, the conduction connecting piece 125 will also be pulled / pressed and other displacement phenomena will occur with the displacement of the battery cell expansion. Reducing the height of the fourth connecting portion 1234 provides a certain space height for the buffer structure design of the conduction connecting piece 125, avoiding the position of the conduction connecting piece 125 being raised due to the setting of the first transition connecting piece 123. On the one hand, it avoids occupying too much space of the battery pack 100, which reduces the space utilization rate of the battery pack 100, and further affects the capacity of the battery pack 100. On the other hand, it avoids the conduction connecting piece 125 being too high to rub with other structures above in the battery pack 100, which affects the structural stability and insulation reliability.

[0093] As shown in FIG. 13, the second transition connecting piece 124 includes a fifth connecting part 1243 and a sixth connecting part 1244 oppositely arranged along the first direction X, the fifth connecting part 1243 is connected with the second output pole connecting piece 1225, the sixth connecting part 1244 is connected with the conduction connecting piece 125, and the sixth connecting part 1244 is sunken toward the second end plate 1222 side along the second direction Z relative to the fifth connecting part 1243. By sinking the sixth connecting part 1244 on the second transition connecting piece 124 toward the second end plate 1222 side along the second direction Z relative to the fifth connecting part 1243, when the second transition connecting piece 124 is connected with the conduction connecting piece 125, the second connecting part 1254 of the conduction connecting piece 125 connected with the second transition connecting piece 124 is located on the sunken sixth connecting part 1244, which reduces the height of the second connecting part 1254. Due to the displacement of the battery cell expansion, the conduction connecting piece 125 will also be pulled / pushed and other displacement phenomena will occur with the displacement of the battery cell expansion. Reducing the height of the fifth connecting part 1243 provides a certain space height for the buffer structure design of the conduction connecting piece 125, avoids the position of the conduction connecting piece 125 being raised due to the setting of the second transition connecting piece 124, which on the one hand avoids occupying too much space of the battery pack 100, reduces the space utilization rate of the battery pack 100, and further affects the capacity of the battery pack 100; on the other hand, avoids the friction between the too high conduction connecting piece 125 and other structures above in the battery pack 100, so as to affect the structural stability and insulation reliability.

[0094] Meanwhile, when the first output pole connecting piece 1215 and the conduction connecting piece 125 are located on the opposite sides of the first transition connecting piece 123 along the second direction Z, and the second output pole connecting piece 1225 and the conduction connecting piece 125 are located on the opposite sides of the second transition connecting piece 124 along the second direction Z, by sinking the fourth connecting part 1234 on the first transition connecting piece 123 toward the first end plate 1212 side along the second direction Z relative to the third connecting part 1233, and sinking the sixth connecting part 1244 on the second transition connecting piece 124 toward the second end plate 1222 side along the second direction Z relative to the fifth connecting part 1243, i.e. the surface of the fourth connecting part 1234 located on the first output pole base 1213 can be flush or substantially flush with the surface of the first output pole connecting piece 1215, and the surface of the sixth connecting part 1244 located on the second output pole base 1223 can be flush or substantially flush with the surface of the second output pole connecting piece 1225, so that the conduction connecting piece 125 does not need to be redesigned due to the setting of the first transition connecting piece 123 and the second transition connecting piece 124, and the original conduction connecting piece 125 can be used, which saves certain research and development cost in the product production and research and development process, and improves the research and development efficiency.

[0095] 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 deformation of the battery module 120 as a whole. At this time, the distance between the end plate at the end of the battery module 120 and the battery cell becomes larger, the transition connecting piece is pulled and is prone to deformation, and even causes poor electrical connection.

[0096] In one embodiment, as shown in FIG. 13, the first transition connecting piece 123 includes a third connecting portion 1233 and a fourth connecting portion 1234 arranged oppositely along the first direction X. The third connecting portion 1233 is connected with the first output pole connecting piece 1215, and the fourth connecting portion 1234 is connected with the conduction connecting piece 125. A first bending portion 1235 is further arranged between the third connecting portion 1233 and the fourth connecting portion 1234 of the first transition connecting piece 123. By arranging the first bending portion 1235 between the third connecting portion 1233 and the fourth connecting portion 1234 of the first transition connecting piece 123, when the first transition connecting piece 123 is subjected to a tensile force, the first bending portion 1235 can absorb the tensile force, avoiding the breakage of the first transition connecting piece 123, causing the electrical connection failure between the battery modules 120, and reducing the service life of the battery pack 100.

[0097] When the fourth connecting portion 1234 of the first transition connecting piece 123 sinks relative to the third connecting portion 1233 along the second direction Z towards the side of the end plate, the first bending portion 1235 is bent to form when the fourth connecting portion 1234 sinks relative to the third connecting portion 1233. Of course, the first bending portion 1235 can be a bending structure that is arched on a plane, and the present disclosure does not limit this.

[0098] As shown in FIG. 13, the second transition connecting piece 124 includes a fifth connecting portion 1243 and a sixth connecting portion 1244 arranged oppositely along the first direction X. The fifth connecting portion 1243 is connected with the second output pole connecting piece 1225, and the sixth connecting portion 1244 is connected with the conduction connecting piece 125. A second bending portion 1245 is further arranged between the fifth connecting portion 1243 and the sixth connecting portion 1244 of the second transition connecting piece 124. Since the battery cell of the battery monomer has the phenomenon of expansion 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 or even breakage of the second transition connecting piece 124, causing the electrical connection failure between the battery modules 120 and reducing the service life of the battery pack 100. By arranging the second bending portion 1245 between the fifth connecting portion 1243 and the sixth connecting portion 1244 of the second transition connecting piece 124, when the second transition connecting piece 124 is subjected to a tensile force, the second bending portion 1245 can absorb the tensile force, avoiding the breakage of the second transition connecting piece 124, causing the electrical connection failure between the battery modules 120, and reducing the service life of the battery pack 100.

[0099] When the sixth connecting portion 1244 of the second transition connecting piece 124 is sunken toward the side of the end plate relative to the fifth connecting portion 1243 along the second direction Z, the second bending portion 1245 is bent along the sinking of the sixth connecting portion 1244 relative to the fifth connecting portion 1243. Of course, the second bending portion 1245 can be a bending structure that is arched on a plane, and the present disclosure does not limit this.

[0100] 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 bending structure 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.

[0101] In one embodiment, as shown in FIGS. 8, 10, and 13, the first transition connecting piece 123 is provided with a first avoiding gap 1236 on one end thereof facing the first output pole connecting piece 1215 along the first direction X, and the first avoiding gap 1236 is used to avoid the position of the electrode connection between the first output pole connecting piece 1215 and the battery monomer. The pole post on the first battery monomer 1211 is usually connected together by laser welding, and after the first transition connecting piece 123 is provided, the first avoiding gap 1236 on the first transition connecting piece 123 can form an avoidance to the welding position of the pole post on the first output pole connecting piece 1215; at the same time, the welding tool for welding the first output pole connecting piece 1215 and the pole post can also be avoided by the first avoiding gap 1236, so as to avoid interference between the first transition connecting piece 123 and the welding tool.

[0102] In one embodiment, as shown in FIGS. 8, 10, and 13, the first transition connecting piece 123 is provided with a first avoiding gap 1236 on one end thereof facing the first output pole connecting piece 1215 along the first direction X, and the first avoiding gap 1236 is used to avoid the position of the electrode connection between the first output pole connecting piece 1215 and the battery monomer. The pole post on the first battery monomer 1211 is usually connected together by laser welding, and after the first transition connecting piece 123 is provided, the first avoiding gap 1236 on the first transition connecting piece 123 can form an avoidance to the welding position of the pole post on the first output pole connecting piece 1215; at the same time, the welding tool for welding the first output pole connecting piece 1215 and the pole post can also be avoided by the first avoiding gap 1236, so as to avoid interference between the first transition connecting piece 123 and the welding tool.

[0103] In one embodiment, as shown in FIG. 8, the first end 1251 of the conducting connecting piece 125 and the first transition connecting piece 123 are fixedly connected to the first output pole base 1213 by the first threaded member 1261. After the first transition connecting piece 123 is arranged on the first output pole base 1213, the first connecting portion 1253 of the conducting connecting piece 125 is then stacked on the first transition connecting piece 123, and the mounting hole on the first connecting portion 1253 is aligned with the mounting hole on the first transition connecting piece 123. Then, the first threaded member 1261 is passed through the mounting holes on the first connecting portion 1253 and the first transition connecting piece 123 and is threadedly connected with the threaded hole on the first output pole base 1213, so as to fix the portion connecting the conducting connecting piece 125 and the first transition connecting piece 123 on the first output pole base 1213, facilitating the installation and dismounting of the conducting connecting piece 125 and the first transition connecting piece 123. Of course, the portion connecting the conducting connecting piece 125 and the first transition connecting piece 123 can also be connected by welding, bonding, clamping or the like, which is not limited in the present disclosure.

[0104] In one embodiment, as shown in FIG. 8, the first end 1251 of the conducting connecting piece 125 and the first transition connecting piece 123 are fixedly connected to the first output pole base 1213 by the first threaded member 1261. After the first transition connecting piece 123 is arranged on the first output pole base 1213, the first connecting portion 1253 of the conducting connecting piece 125 is then stacked on the first transition connecting piece 123, and the mounting hole on the first connecting portion 1253 is aligned with the mounting hole on the first transition connecting piece 123. Then, the first threaded member 1261 is passed through the mounting holes on the first connecting portion 1253 and the first transition connecting piece 123 and is threadedly connected with the threaded hole on the first output pole base 1213, so as to fix the portion connecting the conducting connecting piece 125 and the first transition connecting piece 123 on the first output pole base 1213, facilitating the installation and dismounting of the conducting connecting piece 125 and the first transition connecting piece 123. Of course, the portion connecting the conducting connecting piece 125 and the first transition connecting piece 123 can also be connected by welding, bonding, clamping or the like, which is not limited in the present disclosure.

[0105] In one embodiment, the first transition connecting piece 123 is welded with the first output pole connecting piece 1215. By welding the first transition connecting piece 123 with 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, by welding, the first transition connecting piece 123 and the first output pole connecting piece 1215 can be in full contact, so as to avoid the existence of a gap between the contact surfaces of the first transition connecting piece 123 and the first output pole connecting piece 1215, thereby relatively reducing the contact resistance therebetween, improving the overcurrent capacity and reducing the heat generation.

[0106] The first protruding part is located in the first recessed part. The first protruding part and the first recessed part can be a welding structure left when the first transition connecting piece 123 and the first output pole connecting piece 1215 are welded. By locating the first protruding part in the first recessed part, the connection reliability of the first transition connecting piece 123 and the first output pole connecting piece 1215 is improved.

[0107] The second transition connecting piece 124 and the second output pole connecting piece 1225 are welded. By welding the second transition connecting piece 124 and the second output pole connecting piece 1225, the connection efficiency between the second transition connecting piece 124 and the second output pole connecting piece 1225 is high, and the connection strength is high. At the same time, through welding, the second transition connecting piece 124 and the second output pole connecting piece 1225 can be in full contact, avoiding the existence of gaps between the contact surfaces of the second transition connecting piece 124 and the second output pole connecting piece 1225, so that the contact resistance between the two is relatively low, the overcurrent capacity is improved, and the heat generation is reduced.

[0108] The second protruding part is located in the second recessed part. The second protruding part and the second recessed part can be a welding structure left when the second transition connecting piece 124 and the second output pole connecting piece 1225 are welded. By locating the second protruding part in the second recessed part, the connection reliability of the second transition connecting piece 124 and the second output pole connecting piece 1225 is improved.

[0109] In one embodiment, the resistance of the first transition connecting piece 123 is less than or equal to the resistance of the conduction connecting piece 125, or the resistance of the second transition connecting piece 124 is less than or equal to the resistance of the conduction connecting piece 125, or the resistance of the first transition connecting piece 123 and the second transition connecting piece 124 is less than or equal to the resistance of the conduction connecting piece 125.

[0110] The first output pole connecting piece 1215 and the second output pole connecting piece 1225 can adopt an aluminum bar, and the conduction connecting piece 125 can adopt a copper bar. The first transition connecting piece 123 can adopt a copper bar, so that the resistance of the first transition connecting piece 123 is less than that of the first output pole connecting piece 1215. The second transition connecting piece 124 can also adopt a copper bar, so that the resistance of the second transition connecting piece 124 is less than that of the second output pole connecting piece 1225. When the first transition connecting piece 123 and the second transition connecting piece 124 adopt a copper bar, the resistance is the same as that of the conduction connecting piece 125. Of course, the first transition connecting piece 123 and the second transition connecting piece 124 can also adopt a conductive piece with a resistance between that of a copper bar and that of an aluminum bar, such as a copper-aluminum composite conductive piece.

[0111] When the first transition connecting piece 123 and the second transition connecting piece 124 adopt copper bars, the first output pole connecting piece 1215 and the second output pole connecting piece 1225 adopt aluminum bars, because the materials of the copper bars and the aluminum bars are different, it is not easy to weld, and the soldering method can be used to realize the electrical connection between copper and aluminum, and generally, the soldering needs to melt additional solder to realize the connection between the welding parts; however, the output pole connecting piece and the transition connecting piece are stacked, and it is not easy to operate and difficult to weld if soldering is used, so the common soldering cannot be used; for this purpose, the molecular diffusion welding is used in the present disclosure to realize the electrical connection of the stacked copper-aluminum structure; however, the molecular diffusion welding has high process requirements.

[0112] For this purpose, in one embodiment of the present disclosure, as shown in FIG. 14, the first transition connecting piece 123 includes a first conductive layer 1237 and a second conductive layer 1238 along the second direction Z, the first conductive layer 1237 is located on the side facing the first output pole connecting piece 1215 and has the same material as the first output pole connecting piece 1215, and the second conductive layer 1238 is located on the side facing the on-connecting piece 125 and has the same material as the on-connecting piece 125, that is, the first transition connecting piece 123 is a composite connecting piece, the lower half layer of the composite connecting piece in contact with the aluminum bar is aluminum, and the upper half part in contact with the copper bar is copper, under the condition of meeting the overcurrent requirement, the welding between the first transition connecting piece 123 and the first output pole connecting piece 1215 becomes easier, and the laser welding method can be used to realize the electrical connection, reducing the welding difficulty.

[0113] As shown in FIG. 14, the second transition connecting piece 124 includes a third conductive layer 1247 and a fourth conductive layer 1248 along the second direction Z, the third conductive layer 1247 is located on the side facing the second output pole connecting piece 1225 and has the same material as the second output pole connecting piece 1225, and the fourth conductive layer 1248 is located on the side facing the on-connecting piece 125 and has the same material as the on-connecting piece 125, that is, the second transition connecting piece 124 is a composite connecting piece, the lower half layer of the composite connecting piece in contact with the aluminum bar is aluminum, and the upper half part in contact with the copper bar is copper, under the condition of meeting the overcurrent requirement, the welding between the second transition connecting piece 124 and the second output pole connecting piece 1225 becomes easier, and the laser welding method can be used to realize the electrical connection, reducing the welding difficulty.

[0114] When the first transition connecting piece 123 and the second transition connecting piece 124 adopt the composite connecting piece with the upper half part of copper and the lower half part of aluminum, the thickness of the upper half part of copper can be greater than the thickness of the lower half part of aluminum to reduce the resistance of the composite connecting piece.

[0115] In one embodiment, the first transition connecting piece 123 and the conduction connecting piece 125 are stacked in the second direction Z, and the conduction connecting piece 125 is located on the side of the first transition connecting piece 123 away from the first end plate 1212, that is, the conduction connecting piece 125 is located above the first transition connecting piece 123. One of the first transition connecting piece 123 and the conduction connecting piece 125 is provided with a first protrusion, and the other is provided with a first recess, and the first protrusion is located in the first recess. Through the cooperation of the first protrusion and the first recess, the positioning and cooperation of the first transition connecting piece 123 and the conduction connecting piece 125 can be realized during assembly. If the first transition connecting piece 123 and the conduction connecting piece 125 are both smooth and flat sheet / plate-shaped, manual fixing or pre-fixing with the help of external tooling is required during assembly, which is not convenient for alignment operation, thereby increasing the operation precision of the operator and reducing the production efficiency. The limiting cooperation of the first protrusion and the first recess facilitates the pre-positioning of the first transition connecting piece 123 and the conduction connecting piece 125 to the module during fixing, speeds up the installation and alignment of the first threaded part 1261, and thus speeds up the production and improves the production efficiency.

[0116] In one embodiment, the first transition connecting piece 123 and the conduction connecting piece 125 are stacked in the second direction Z, and the conduction connecting piece 125 is located on the side of the first transition connecting piece 123 away from the first end plate 1212, that is, the conduction connecting piece 125 is located above the first transition connecting piece 123. One of the first transition connecting piece 123 and the conduction connecting piece 125 is provided with a first protrusion, and the other is provided with a first recess, and the first protrusion is located in the first recess. Through the cooperation of the first protrusion and the first recess, the positioning and cooperation of the first transition connecting piece 123 and the conduction connecting piece 125 can be realized during assembly. If the first transition connecting piece 123 and the conduction connecting piece 125 are both smooth and flat sheet / plate-shaped, manual fixing or pre-fixing with the help of external tooling is required during assembly, which is not convenient for alignment operation, thereby increasing the operation precision of the operator and reducing the production efficiency. The limiting cooperation of the first protrusion and the first recess facilitates the pre-positioning of the first transition connecting piece 123 and the conduction connecting piece 125 to the module during fixing, speeds up the installation and alignment of the first threaded part 1261, and thus speeds up the production and improves the production efficiency.

[0117] The outer circumferential size of the first recessed part is greater than the outer circumferential size of the first protruding part, and in the direction in which the first transition connecting piece 123 and the conduction connecting piece 125 are stacked, the diameter of the first protruding part decreases towards the first recessed part, and the height of the first protruding part is greater than the depth of the first recessed part. By making the outer circumferential size of the first recessed part greater than the outer circumferential size of the first protruding part, that is, a certain assembly gap / allowance is reserved, the operating precision of the operator is reduced, and the production efficiency can be accelerated; at the same time, the diameter of the first protruding part decreases towards the first recessed part, and the first protruding part can be regarded as a stepped structure with a large base and a small head and a trapezoidal cross section, and the first protruding part with a large base and a small head is inserted into the first recessed part, which has a guiding effect; along the height direction, the height of the first protruding part is greater than the depth of the first recessed part, and due to the downward force caused by the fastening of the first threaded part 1261, the first protruding part deforms to fill the first recessed part during the crimping process, so that the conduction connecting piece 125 and the first transition connecting piece 123 are tightly matched, and the structural stability is improved. In addition, the tight fit of the first protruding part and the first recessed part can increase the electrical connection area between the first transition connecting piece 123 and the conduction connecting piece 125, thereby improving the overcurrent capacity, reducing heat generation, and avoiding thermal safety accidents.

[0118] The outer circumferential size of the second recessed part is greater than the outer circumferential size of the second protruding part, and in the direction in which the second transition connecting piece 124 and the conduction connecting piece 125 are stacked, the diameter of the second protruding part decreases towards the second recessed part, and the height of the second protruding part is greater than the depth of the second recessed part. By making the outer circumferential size of the second recessed part greater than the outer circumferential size of the second protruding part, that is, a certain assembly gap / allowance is reserved, the operating precision of the operator is reduced, and the production efficiency can be accelerated; at the same time, the diameter of the second protruding part decreases towards the second recessed part, and the second protruding part with a large base and a small head is inserted into the second recessed part, which has a guiding effect; along the height direction, the height of the second protruding part is greater than the depth of the second recessed part, and due to the downward force caused by the fastening of the second threaded part 1262, the second protruding part deforms to fill the second recessed part during the crimping process, so that the conduction connecting piece 125 and the second transition connecting piece 124 are tightly matched, and the structural stability is improved. In addition, the tight fit of the second protruding part and the second recessed part can increase the electrical connection area between the second transition connecting piece 124 and the conduction connecting piece 125, thereby improving the overcurrent capacity, reducing heat generation, and avoiding thermal safety accidents.

[0119] As shown in FIGS. 12 and 13, the through connection piece 125 is provided with a first through hole 1257, the first transition connection piece 123 is provided with a second through hole 1239, the first transition connection piece 123 and the through connection piece 125 are fixed on the first end plate 1212 by a first threaded part 1261 passing through the first through hole 1257 and the second through hole 1239, and the diameter of the first through hole 1257 is greater than the diameter of the second through hole 1239. Although the first protruding part and the first recessed part can be positioned by cooperation, when the first through hole 1257 and the second through hole 1239 have the same size, only the approximate limiting position can be estimated, and then manual small-range translation is needed to finally realize the alignment of the first protruding part and the first recessed part. However, since the through connection piece 125 and the first transition connection piece 123 are both metal, the translation will cause scratching phenomenon, resulting in small metal particles. Under the working condition of the battery module 120, the small metal particles are free in each position of the module, which can easily cause short circuit safety accidents. By making the first through hole 1257 on the through connection piece 125 larger than the second through hole 1239 on the first transition connection piece 123, when the first protruding part and the first recessed part of the through connection piece 125 and the first transition connection piece 123 are cooperated, it is convenient to intuitively see whether the second through hole 1239 of the first transition connection piece 123 is aligned or not through the larger first through hole 1257 on the through connection piece 125, which reduces the operation precision, more accurately realizes the alignment, improves the production efficiency, and reduces the risk of safety accidents.

[0120] As shown in FIGS. 12 and 13, the through connection piece 125 is provided with a third through hole 1258, the second transition connection piece 124 is provided with a fourth through hole 1249, the second transition connection piece 124 and the through connection piece 125 are fixed on the second end plate 1222 by a second threaded part 1262 passing through the third through hole 1258 and the fourth through hole 1249, and the diameter of the third through hole 1258 is greater than the diameter of the fourth through hole 1249. By making the third through hole 1258 on the through connection piece 125 larger than the fourth through hole 1249 on the second transition connection piece 124, when the second protruding part and the second recessed part of the through connection piece 125 and the second transition connection piece 124 are cooperated, it is convenient to intuitively see whether the fourth through hole 1249 of the second transition connection piece 124 is aligned or not through the larger third through hole 1258 on the through connection piece 125, which reduces the operation precision, more accurately realizes the alignment, improves the production efficiency, and reduces the risk of safety accidents.

[0121] The first transition connecting piece 123 is provided with a first recess, and the through connecting piece 125 is provided with a first protrusion. The first protrusion surrounds the first via 1257, and the part of the through connecting piece 125 surrounding the first via 1257 protrudes towards the side of the first transition connecting piece 123, forming the first protrusion on the side of the first transition connecting piece 123, forming a first sunken platform on the side away from the first transition connecting piece 123, and the first threaded part 1261 is located in the first sunken platform. Since the fixed through connecting piece 125 and the first threaded part 1261 on the first transition connecting piece 123 are electrified, the third threaded part 1263 on the first end plate 1212 for defining the first end plate 1212 is not electrified, and the creepage path of the first threaded part 1261 and the third threaded part 1263 passes through the first side plate 12133 of the first output pole base 1213. By arranging the first sunken platform surrounding the first via 1257, the end of the first threaded part 1261 is located in the first sunken platform, the height of the first threaded part 1261 on the first output pole base 1213 is reduced, the creepage distance between the first threaded part 1261 and the third threaded part 1263 is relatively increased, and short circuit between the through connecting piece 125 and the first end plate 1212 is avoided, and the safety performance of the battery pack 100 is further improved.

[0122] The second transition connecting piece 124 is provided with a second recess, and the through connecting piece 125 is provided with a second protrusion. The second protrusion surrounds the third via 1258, and the part of the through connecting piece 125 surrounding the third via 1258 protrudes towards the side of the second transition connecting piece 124, forming the second protrusion on the side of the second transition connecting piece 124, forming a second sunken platform on the side away from the second transition connecting piece 124, and the second threaded part 1262 is located in the second sunken platform. By arranging the second sunken platform surrounding the third via 1258, the end of the second threaded part 1262 is located in the second sunken platform, the height of the second threaded part 1262 on the second output pole base 1223 is reduced, the creepage distance between the second threaded part 1262 and the fourth threaded part 1264 is relatively increased, and short circuit between the through connecting piece 125 and the second end plate 1222 is avoided, and the safety performance of the battery pack 100 is further improved.

[0123] As shown in FIGS. 5 and 6, the first base cover plate 1214 can be arranged on the first output pole base 1213. The first base cover plate 1214 and the first output pole base 1213 are both made of insulating material. The first base cover plate 1214 can form an insulating space together with the first output pole base 1213, so as to insulate 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 part 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 part 1261 at the first output pole base 1213.

[0124] As shown in FIGS. 5 and 6, the second base cover plate 1224 can be arranged on the second output pole base 1223. The second base cover plate 1224 and the second output pole base 1223 are both made of insulating material. The second base cover plate 1224 can form an insulating space together with the second output pole base 1223, so as to insulate 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 part 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 part 1262 at the second output pole base 1223.

[0125] In an embodiment, as shown in FIGS. 12 and 13, the first through hole 1257 and the third through hole 1258 on the conduction connecting piece 125, the second through hole 1239 on the first transition connecting piece 123 and the fourth through hole 1249 on the second transition connecting piece 124 can all be waist round holes extending along the first direction X. By setting the first through hole 1257, the second through hole 1239, the third through hole 1258 and the fourth through hole 1249 as waist round holes, on the one hand, the connection positions of the conduction connecting piece 125, the first transition connecting piece 123 and the second transition connecting piece 124 in the first direction X can be adjusted, the tolerance requirement of the components is reduced, and the assembly precision is improved. On the other hand, when the spacing between the first battery module 121 and the second battery module 122 changes due to displacement, the conduction connecting piece 125 will be affected to stretch, and the relative positions between the conduction connecting piece 125, the first transition connecting piece 123 and the second transition connecting piece 124 will change. The waist round holes can absorb the change of the relative positions between the conduction connecting piece 125, the first transition connecting piece 123 and the second transition connecting piece 124, so as to avoid the deformation or even fracture of the first threaded part 1261 and the second threaded part 1262 caused by the shear stress of the first threaded part 1261 and the second threaded part 1262 due to the change of the positions between the conduction connecting piece 125, the first transition connecting piece 123 and the second transition connecting piece 124.

[0126] In one embodiment, the plurality of battery modules 120 includes a plurality of groups of the first battery module 121 and the second battery module 122, the plurality of groups of the first battery module 121 and the second battery module 122 are arranged along the third direction Y; the first battery module 121 and the second battery module 122 in each group are both provided with the first output pole base 1213, the second output pole base 1223, and the conductive connecting piece 125 provided with the insulating layer 1256; meanwhile, the first battery module 121 and the second battery module 122 in each group can also be both provided with the first transition connecting piece 123 and the second transition connecting piece 124, further improving the safety performance of the battery pack 100.

[0127] In the embodiments of the present disclosure, the terms "first", "second", "third" are only for the purpose of description and cannot be understood as indicating or implying relative importance; the term "plurality" refers to two or more, unless otherwise explicitly limited. The terms "mounting", "connecting", "connecting", "fixing" and the like should be broadly understood, for example, "connecting" can be fixed connection, can also be detachable connection, or integrally connected; "connected" can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in the embodiments of the present disclosure can be understood according to the specific circumstances.

[0128] In the description of the embodiments of the present disclosure, it should be understood that the terms "upper", "lower", "left", "right", "front", "back" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the embodiments of the present disclosure and simplifying the description, and do not indicate or imply that the devices or units referred to must have a particular direction, be constructed and operated in a particular orientation, therefore, cannot be understood as a limitation on the embodiments of the present disclosure.

[0129] In the description of the present disclosure, the terms "one embodiment", "some embodiments", "a specific embodiment" and the like mean 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 present disclosure. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0130] Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the features disclosed herein. It is intended that the disclosure be construed as including any patents, patent applications, publications, publications, or other disclosure of complementary subject matter that is within the scope of the disclosure. It is intended that the specification and examples be considered exemplary only, with the true scope and spirit of the disclosure being indicated by the following claims.

Claims

1. A battery pack, comprising: a battery box formed with a battery compartment; a plurality of battery modules located in the battery compartment; each of the battery modules comprises a plurality of battery cells arranged along a first direction and end plates clamped at both ends of the plurality of battery cells; the plurality of battery modules at least comprises a first battery module and a second battery module arranged adjacent along the first direction, a first output pole base insulated is provided on a 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; a second output pole base insulated is provided on a 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; the first output pole base is provided on one side of the first end plate along a second direction, the second output pole base is provided on one side of the second end plate along the second direction, and the second direction intersects the first direction; a conduction connecting piece comprising a first connecting part, a second connecting part and an intermediate connecting part located between the first connecting part and the second connecting part, the first connecting part is connected with the first output pole connecting piece on the first output pole base, and the second connecting part is connected with the second output pole connecting piece on the second output pole base; a first transition connecting piece located on the first output pole base, the first transition connecting piece comprises a third connecting part and a fourth connecting part oppositely arranged along the first direction, the third connecting part is connected with the first output pole connecting piece, the fourth connecting part is connected with the conduction connecting piece, and the fourth connecting part is sunken relative to the third connecting part along the second direction towards one side of the first end plate; a surface of the fourth connecting part along the second direction away from the first end plate is flush or substantially flush with a surface of the first output pole connecting piece along the second direction away from the battery cell; a second transition connecting piece located on the second output pole base, the second transition connecting piece comprises a fifth connecting part and a sixth connecting part oppositely arranged along the first direction, the fifth connecting part is connected with the second output pole connecting piece, the sixth connecting part is connected with the conduction connecting piece, and the sixth connecting part is sunken relative to the fifth connecting part along the second direction towards one side of the second end plate; a surface of the sixth connecting part along the second direction away from the second end plate is flush or substantially flush with a surface of the second output pole connecting piece along the second direction away from the battery cell; wherein an insulating layer is provided on a surface of the intermediate connecting part, and the insulating layer has an overlapping portion with the first output pole base and the second output pole base along the first direction.

2. The battery pack of claim 1, wherein, At least part of the intermediate connecting part is in a bending structure, and the bending structure can move the first connecting part and the second connecting part away from or towards each other along the first direction.

3. The battery pack of claim 2, wherein, When the first connecting part and the second connecting part move away from each other along the first direction, the intermediate connecting part in the bent structure is in a flat state, and the insulating layer has an overlapping part with the first output pole base and the second output pole base in the first direction.

4. The battery pack of claim 2 or 3, wherein, The insulating layer is made of elastic material, and can stretch or contract when the first connecting part and the second connecting part move away from or towards each other along the first direction.

5. The battery pack of claim 4, wherein, The insulating layer is bonded to the conductive connecting sheet.

6. The battery pack of claim 5, wherein, The insulating layer is an insulating adhesive tape.

7. The battery pack of claim 1, wherein, The first output pole base is provided with a first extension part extending towards the first end plate, and the first extension part has an overlapping part with the first end plate in the second direction; and / or, the second output pole base is provided with a second extension part extending towards the second end plate, and the second extension part has an overlapping part with the second end plate in the second direction.

8. The battery pack of claim 1, wherein, The first output pole base is provided with a first side plate extending towards the second direction on both sides in a third direction; in the second direction, the height of the first side plate is greater than the thickness of the first connecting part; and / or, the second output pole base is provided with a second side plate extending towards the second direction on both sides in the third direction; in the second direction, the height of the second side plate is greater than the thickness of the second connecting part. The third direction intersects with the first direction and the second direction.

9. The battery pack of claim 8, wherein, When the first output pole base is provided with the first side plate, the first side plate is provided with a first protruding part extending towards the second end plate in the first direction, and the first protruding part protrudes from the first end plate in the first direction; and / or, when the second output pole base is provided with the second side plate, the second side plate is provided with a second protruding part extending towards the first end plate in the second direction, and the second protruding part protrudes from the second end plate in the first direction.

10. The battery pack of claim 1, wherein, The first output pole base includes a first base between the first connecting part and the first end plate, and the first base is provided with a first protruding part extending towards the second end plate in the first direction, and the first protruding part protrudes from the first end plate in the first direction; and / or, the second output pole base includes a second base between the second connecting part and the second end plate, and the second base is provided with a second protruding part extending towards the first end plate in the first direction, and the second protruding part protrudes from the second end plate in the first direction.

11. The battery pack of claim 1, wherein, The resistance of the first transition connecting sheet is smaller than the resistance of the first output pole connecting sheet, and the resistance of the second transition connecting sheet is smaller than the resistance of the second output pole connecting sheet.

12. The battery pack of claim 11, wherein, The first transition connecting piece and one of the conductive connecting pieces are provided with a first protrusion, and the other is provided with a first recess, and the first protrusion is located in the first recess; and / or the second transition connecting piece and one of the conductive connecting pieces are provided with a second protrusion, and the other is provided with a second recess, and the second protrusion is located in the second recess.

13. The battery pack of claim 12, wherein, The outer circumferential size of the first recess is greater than the outer circumferential size of the first protrusion, and in the direction in which the first transition connecting piece and the conductive connecting piece are stacked, the diameter of the first protrusion decreases towards the first recess, and the height of the first protrusion is greater than the depth of the first recess; and / or the outer circumferential size of the second recess is greater than the outer circumferential size of the second protrusion, and in the direction in which the second transition connecting piece and the conductive connecting piece are stacked, the diameter of the second protrusion decreases towards the second recess, and the height of the second protrusion is greater than the depth of the second recess.

14. The battery pack of claim 12, wherein, The conductive connecting piece is provided with a first through hole, the first transition connecting piece is provided with a second through hole, the first transition connecting piece and the conductive connecting piece are fixed on the first end plate by a first threaded member passing through the first through hole and the second through hole, and the diameter of the first through hole is greater than the diameter of the second through hole; and / or the conductive connecting piece is provided with a third through hole, the second transition connecting piece is provided with a fourth through hole, the second transition connecting piece and the conductive connecting piece are fixed on the second end plate by a second threaded member passing through the third through hole and the fourth through hole, and the diameter of the third through hole is greater than the diameter of the fourth through hole.

15. The battery pack of claim 14, wherein, The first transition connecting piece is provided with the first recess, and the conductive connecting piece is provided with the first protrusion; the first protrusion surrounds the first through hole, and the part of the conductive connecting piece surrounding the first through hole protrudes towards the side of the first transition connecting piece, forms the first protrusion on the side towards the first transition connecting piece, forms a first sunken platform on the side away from the first transition connecting piece, and the first threaded member is located in the first sunken platform; and / or the second transition connecting piece is provided with the second recess, and the conductive connecting piece is provided with the second protrusion; the second protrusion surrounds the third through hole, and the part of the conductive connecting piece surrounding the third through hole protrudes towards the side of the second transition connecting piece, forms the second protrusion on the side towards the second transition connecting piece, forms a second sunken platform on the side away from the second transition connecting piece, and the second threaded member is located in the second sunken platform.

16. The battery pack of claim 1, wherein, The plurality of battery modules includes a plurality of groups of the first battery module and the second battery module, and the plurality of groups of the first battery module and the second battery module are arranged along a third direction; the first battery module and the second battery module in each group are connected by the conductive connecting piece; and the third direction intersects the first direction and the second direction.

17. An energy storage system comprising the battery pack of any one of claims 1-16.

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