Battery pack structure of lithium battery for electric motorcycle

Abstract

The present application relates to the field of two-wheeled motorcycle lithium battery battery pack, and particularly relates to a battery pack structure of lithium battery for electric motorcycle, which comprises a box body, a battery cell, a liquid cooling device, a heating device and a plurality of components, the box body comprises an upper box body and a lower box body, the upper box body and the lower box body are connected, the battery cell, the liquid cooling device and the heating device are all installed in the lower box body, the liquid cooling device and the heating device are located at the lower part of the battery cell, the liquid cooling device is arranged on the bottom plate of the lower box body, the heating device is arranged on the liquid cooling device, the battery cell and the plurality of components are connected through copper bars, the plurality of components are installed in the upper box body, and a mica plate is arranged between the upper box body and the lower box body, so that the problems of the existing battery pack for electric motorcycle at the present stage, such as the lack of active thermal management in most low-end battery packs, the easy over-temperature of large current, climbing and fast charging, the fast discharge at low temperature, the defects of BMS function and the low internal safety protection configuration of the battery pack are solved.

Description

Technical Field

[0001] This invention relates to the field of lithium battery packs for two-wheeled motorcycles, and more specifically to a battery pack structure for lithium batteries used in electric motorcycles. Background Technology

[0002] The battery pack for electric motorcycles is the core power source, a key component determining the vehicle's range, power, safety, and operating costs. With the global shift towards new energy transportation and the explosive growth in urban short-distance travel demand, electric motorcycle battery packs have evolved from simple assembly of early lead-acid batteries to integrated products centered on lithium-ion batteries, incorporating intelligent management and safety protection. This has become a core area for technological upgrading and market competition in the electric motorcycle industry. Currently, the industry is at a critical stage of lithium-ion battery substitution, compliance upgrades, and intelligent iterations. Technological innovation and policy regulations are jointly driving products towards higher safety, longer lifespan, higher cost-effectiveness, and ecological sustainability.

[0003] The revised "Safety Requirements for Lithium-ion Batteries for Electric Motorcycles and Electric Mopeds" (GB36672-XXXX), issued in 2025, replaces the original 2018 standard, significantly strengthening safety requirements. It adds tests such as seawater immersion, thermal diffusion, and extrusion, optimizes protection indicators for overcharging, overheating, and vibration, and clarifies the marking of individual battery cells and battery packs, as well as the rules for determining the same type. This ensures product safety throughout the entire process from design, production, and testing. By combining with national standards such as "Safety Requirements for Electric Vehicles," electric motorcycle battery packs must meet automotive-grade requirements such as IP67 waterproof and dustproof performance and vibration and shock resistance. The new national standard's status as a motor vehicle for electric motorcycles also requires battery packs to be compatible with the vehicle for registration and testing, making compliance a basic entry barrier for companies.

[0004] The battery pack of an electric motorcycle is the "heart" of the motorcycle. It is transitioning from lead-acid to lithium batteries. The core features are high energy density, high rate capability, high safety, and low cost. The mainstream is 48 / 60 / 72V, targeting commuting / modification / high-speed scenarios. Higher requirements are placed on the high cost ratio, safety and thermal management, and the balance between fast charging and lifespan. This also places higher demands on the design and production of battery companies.

[0005] Current battery packs for electric motorcycles have the following problems:

[0006] 1. Most mid-to-low-end battery packs for electric motorcycles currently lack active thermal management, making them prone to overheating during high current, hill climbing, and fast charging; they also discharge quickly at low temperatures, resulting in a 30%-50% reduction in capacity.

[0007] 2. The IP67 standard is not widely adopted, and water and dust can easily cause short circuits; vibration and impact can loosen the cell connections and cause malfunctions.

[0008] 3. BMS functional defects: Most mid-to-low-end vehicles use passive balancing, without accurate SOC and SOH estimation, and the overcharge, over-discharge and overcurrent protection thresholds are loose, which accelerates degradation. Currently, the mainstream BMS configuration on the market uses protection boards.

[0009] 4. The battery pack has low internal safety protection features.

[0010] At present, a battery pack structure for lithium batteries used in electric motorcycles is proposed to solve the problems mentioned in the background art. Summary of the Invention

[0011] The purpose of this invention is to provide a battery pack structure for lithium batteries used in electric motorcycles, which improves battery pack thermal management, system control, cell fixing, and cell thermal runaway protection, thus solving the problems mentioned in the background art.

[0012] A battery pack structure for a lithium battery used in electric motorcycles includes a housing, battery cells, a liquid cooling device, a heating device, and several components. The housing includes an upper housing and a lower housing, which are connected. The battery cells, liquid cooling device, and heating device are all installed in the lower housing. The liquid cooling device and heating device are located below the battery cells. The liquid cooling device is disposed on the bottom plate of the lower housing, and the heating device is disposed on the liquid cooling device. The battery cells and the several components are connected by copper busbars. The several components are installed in the upper housing. A mica plate is disposed between the upper housing and the lower housing.

[0013] Further defining the liquid cooling device, it includes a liquid cooling plate, an inlet, and an outlet. The liquid cooling plate and the bottom plate of the lower housing are integrated to form a liquid cooling base plate. The liquid cooling base plate is made of a porous extruded profile and is sealed to allow coolant to flow through it. The inlet and outlet are both connected to the liquid cooling base plate through water pipes.

[0014] Further specifying, the heating device is a heating film, which is adhered to the liquid-cooled base plate. The heating film contains heating wires of different power to balance the temperature difference at the bottom. The wire exit position of the heating film is set in an arc shape. The left and right sides of the lower housing are provided with wire exit contouring mechanisms, which are also arc-shaped and set to match the wire exit position of the heating film. The heating film heats the bottom of the battery cell to achieve low-temperature charging heating and low-temperature environment start-up heating of the battery.

[0015] Further specified, the bottom of the battery cell, the heating film, and the liquid-cooled base plate are all filled with thermally conductive structural adhesive, and the left and right sides of the battery cell and the lower casing are filled with expanding foam.

[0016] Further specified, the battery cell is composed of several ternary lithium batteries, which are separated by aerogel. The mica plate isolates the battery cell from the other components. A CCS assembly is provided on the battery cell, and a data acquisition harness and busbar are provided on the CCS assembly.

[0017] Further specifying, the aforementioned components include a BDU and a BMS, the BMS and the BDU being integrated on an electrical board, the BDU integrating a main positive relay, a charging relay, a pre-charge resistor, and a shunt, the electrical board also having a protective cover covering the BMS and BDU, and the upper housing having a charging plug and a discharging plug, both of which are connected to the BMS and BDU via wiring harnesses.

[0018] Further specifying, the lower part of the upper housing is provided with a sealant groove and bolt holes, the sealant groove is filled with sealant, and bolts are provided in the bolt holes, and the upper housing is sealed to the lower housing through the sealant and bolts.

[0019] Further specifying, the upper part of the upper housing is provided with an inspection port, and also includes an inspection cover, the inspection cover being sealed and installed at the inspection port of the upper housing.

[0020] Furthermore, the upper housing is also equipped with an explosion-proof pressure relief valve, and the explosion-proof pressure relief valve is equipped with a directional exhaust channel.

[0021] The advantages of this invention compared to the prior art are as follows:

[0022] 1. The heating wires inside the heating film use different power distributions to balance the temperature difference at the bottom; the liquid cooling is integrated into the bottom plate of the enclosure. The bottom plate uses a multi-hole extruded profile, and through a reasonable structure, the coolant circulates inside to dissipate heat from the battery pack.

[0023] 2. The BMS and BDU are integrated into one unit; compared with the protection board, it has the following advantages: system-level intelligent management; adaptable to high voltage and high current scenarios; and has the following functions: cell voltage acquisition, charging and discharging current acquisition, cell temperature acquisition, charging and discharging relay, pre-charge relay, heating relay control, KEY switch detection, charger detection, CAN communication, accurate estimation of insulation detection status, active balancing, remote monitoring, etc.; multi-level redundancy and fault diagnosis.

[0024] 3. The bottom of the battery cell is bonded to the casing using thermally conductive structural adhesive, and the space between the battery cell and the bottom heating film is also filled with thermally conductive structural adhesive. This allows for faster heat transfer between the battery cell and the casing, whether for heating or cooling. The sides are filled with expanding foam, which serves both to fix the battery cell and to provide insulation.

[0025] 4. Aerogel is used between the cells; mica plates are used to isolate the cells from the upper electrical components and copper busbars to prevent thermal runaway of the cells. Attached Figure Description

[0026] Figure 1 This is an exploded view of the present invention;

[0027] Figure 2 This is a bottom view of the upper housing of the present invention;

[0028] Figure 3 This is a schematic diagram of the lower housing of the present invention;

[0029] Figure 4 This is a schematic diagram of the battery cell and CCS assembly of the present invention.

[0030] Figure 5 This is a schematic diagram of the components of the present invention.

[0031] The markings in the diagram correspond to: 1-Upper housing, 111-Sealing groove, 112-Bolt hole, 113-Inspection port, 114-Sealing ring, 2-Lower housing, 3-Inspection cover, 4-Battery cell, 5-Liquid cooling base plate, 6-Water inlet, 7-Water outlet, 8-Heating film, 9-Cable guide mechanism, 10-Thermal conductive structural adhesive, 11-Foaming adhesive, 12-Mica board, 13-CCS assembly, 14-BDU, 15-BMS, 16-Electrical board, 17-Protective cover, 18-Charging plug, 19-Discharging plug, 20-Copper busbar, 21-Explosion-proof pressure relief valve. Detailed Implementation

[0032] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0033] Example:

[0034] like Figures 1-5As shown, a battery pack structure for a lithium battery used in an electric motorcycle includes a housing, battery cells, a liquid cooling device, a heating device, and several components. The housing includes an upper housing 1 and a lower housing 2, with a mica plate 12 disposed between the upper housing 1 and the lower housing 2. The lower part of the upper housing 1 has a sealing groove 111 and bolt holes 112. The sealing groove 111 is filled with sealant, and bolts are installed in the bolt holes 112. The upper housing 1 is sealed to the lower housing 2 by the sealant and bolts. The upper part of the upper housing has an inspection port 113, and also includes an inspection cover 3, which is sealed and installed at the inspection port 114 of the upper housing 1. The inspection port 114 is sealed with an EPDM sealing ring 114 and bolts. The battery cell 4, liquid cooling device and heating device are all installed in the lower housing 2. The liquid cooling device and heating device are located at the bottom of the battery cell 4. The battery cell 4 and several components are connected by copper busbars. The liquid cooling device includes a liquid cooling plate, a water inlet 6 and a water outlet 7. The liquid cooling plate 5 and the bottom plate of the lower housing 2 are integrated to form a liquid cooling bottom plate 5. The liquid cooling bottom plate 5 is made of porous extruded profile and sealed with a reasonable structure to allow the coolant to flow in it. The water inlet 6 and the water outlet 7 are both connected to the liquid cooling bottom plate 5 through water pipes.

[0035] The heating device is a heating film 8, which is attached to the liquid-cooled base plate 5. Heating wires of different powers are distributed inside the heating film 8 to balance the temperature difference at the bottom. The position of the heating film 8 is set in an arc shape. The left and right sides of the lower box 2 are provided with wire exit contouring mechanisms 9, which are also arc-shaped and set to match the wire exit position of the heating film 8. The heating film 8 achieves low-temperature charging heating and low-temperature environment start-up heating of the battery by heating the bottom of the battery cell 4. Thermally conductive structural adhesive 10 is filled between the bottom of the battery cell 4, the heating film 8, and the liquid-cooled base plate 5. Foaming adhesive 11 is filled between the left and right sides of the battery cell 4 and the lower box 2. The thermally conductive structural adhesive 15 can be applied by a robot. The thickness of the adhesive can be controlled by the limit adhesive strip attached to the bottom of the box. The thickness of the adhesive is 0.8mm. The foaming adhesive 11 on both sides is filled manually and sealed by a pressing tool.

[0036] The battery cell 4 is composed of several ternary lithium batteries, which are separated by aerogel. The mica plate 12 isolates the battery cell 4 from the components. The battery cell 4 is also equipped with a CCS assembly 13, which is equipped with a data acquisition harness and a busbar.

[0037] Several components, including BDU14 and BMS15, are integrated on the electrical board 16. BDU14 integrates a main positive relay, a charging relay, a pre-charge resistor, and a shunt. The electrical board 16 is also equipped with a protective cover 17, which covers BMS15 and BDU14. Charging plug 18 and discharging plug 19 are provided on the outside of the upper housing 1. Both charging plug 18 and discharging plug 19 are connected to BMS15 and BDU14 through wiring harnesses. The battery cell 4 and several components are connected through copper busbars 20.

[0038] The mica plate 12 is arranged between the battery cell 4 and the components. If the battery cell 4 experiences thermal runaway, it isolates the high temperature from the components and ensures their safety. At the same time, it slows down the spread of thermal runaway, giving the occupants more time to take action. The aerogel between the battery cells 4 is used to better block thermal runaway of adjacent battery cells 4. If a battery cell experiences thermal runaway, the aerogel has a thermal insulation effect, adding another layer of protection to the safety of the entire battery pack.

[0039] In addition to facilitating the battery pack production and assembly process, the inspection port 113 also facilitates after-sales maintenance. The battery pack can be inspected simply by opening the inspection cover 3.

[0040] The upper housing 1 is also equipped with an explosion-proof pressure relief valve 21. When the battery experiences thermal runaway (such as short circuit, overcharge, or puncture), a large amount of gas will be generated inside, and the pressure will rise sharply. The explosion-proof pressure relief valve 21 will automatically open under the set pressure to release the gas and prevent the housing from being ruptured and causing an explosion. The explosion-proof pressure relief valve 21 is designed with a directional exhaust channel, which can guide high-temperature, flammable gases and flames to a safe area (such as away from the passenger compartment and away from electrical components) to reduce the risk of secondary injury. In addition, the explosion-proof pressure relief valve 21 contains a breathable valve to prevent external dust and moisture from entering the battery pack, meeting the IP67 rating.

[0041] The above provides a detailed description of the battery pack structure for a lithium battery used in electric motorcycles provided by the present invention. The specific embodiments are only used to help understand the method and core ideas of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A battery pack structure for a lithium battery used in electric motorcycles, characterized in that: The device includes a housing, a battery cell (4), a liquid cooling device, a heating device, and several components. The housing includes an upper housing (1) and a lower housing (2), which are connected. The battery cell (4), the liquid cooling device, and the heating device are all installed in the lower housing (2). The liquid cooling device and the heating device are located at the bottom of the battery cell (4). The liquid cooling device is set on the bottom plate of the lower housing (2), and the heating device is set on the liquid cooling device. The battery cell (4) and the several components are connected by a copper busbar (20). The several components are installed in the upper housing (1), and a mica plate (12) is provided between the upper housing (1) and the lower housing (2).

2. The battery pack structure for a lithium battery for an electric motorcycle according to claim 1, characterized in that: The liquid cooling device includes a liquid cooling plate, an inlet (6) and an outlet (7). The liquid cooling plate and the bottom plate of the lower box (2) are integrated to form a liquid cooling bottom plate (5). The liquid cooling bottom plate (5) is made of a porous extruded profile and is sealed to allow the coolant to flow through it. The inlet (6) and the outlet (7) are both connected to the liquid cooling bottom plate (5) through water pipes.

3. The battery pack structure for a lithium battery for an electric motorcycle according to claim 2, characterized in that: The heating device is a heating film (8), which is attached to the liquid-cooled base plate (5). The heating film (8) has heating wires of different powers distributed inside to balance the bottom heating temperature difference. The outlet position of the heating film (8) is set in an arc shape. The left and right sides of the lower box (2) are provided with an outlet contouring mechanism (9). The outlet contouring mechanism (9) is arc-shaped and is set in accordance with the outlet position of the heating film (8). The heating film (8) heats the bottom of the battery cell (4) to realize the low-temperature charging heating and low-temperature environment start-up heating of the battery.

4. The battery pack structure for a lithium battery for an electric motorcycle according to claim 3, characterized in that: Thermally conductive structural adhesive (10) is filled between the bottom of the battery cell (4), the heating film (8), and the liquid cooling base plate (5), and foam adhesive (11) is filled between the left and right sides of the battery cell (4) and the lower housing (2).

5. The battery pack structure for a lithium battery for an electric motorcycle according to claim 1, characterized in that... The battery cell (4) is composed of several ternary lithium batteries, and aerogel is used between the several ternary lithium batteries. The mica plate (12) isolates the battery cell (4) from the several components. The battery cell (4) is provided with a CCS assembly (13), and the CCS assembly (13) is provided with a data acquisition harness and a busbar.

6. The battery pack structure for a lithium battery for an electric motorcycle according to claim 4, characterized in that: The aforementioned components include a BDU (14) and a BMS (15). The BMS (15) and the BDU (14) are integrated on an electrical board (16). The BDU (14) integrates a main positive relay, a charging relay, a pre-charging resistor, and a shunt. The electrical board (16) is also provided with a protective cover (17), which covers the BMS (15) and the BDU (14). The upper housing (1) is provided with a charging plug (18) and a discharging plug (19). The charging plug (18) and the discharging plug (19) are both connected to the BMS (15) and the BDU (14) via wiring harnesses.

7. The battery pack structure for a lithium battery for an electric motorcycle according to claim 1, characterized in that: The lower part of the upper box (1) is provided with a sealant groove (111) and a bolt hole (112). The sealant groove (111) is filled with sealant, and the bolt hole (112) is provided with a bolt. The upper box (1) is sealed to the lower box (2) through the sealant and the bolt.

8. The battery pack structure for a lithium battery for an electric motorcycle according to claim 1, characterized in that: The upper housing (1) is provided with an inspection port (113) and also includes an inspection cover (3), which is sealed and installed at the inspection port (113) of the upper housing (1).

9. The battery pack structure for a lithium battery for an electric motorcycle according to claim 1, characterized in that: The upper housing (1) is also provided with an explosion-proof pressure relief valve (21), and the explosion-proof pressure relief valve (21) is provided with a directional exhaust channel.

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