MAEVING Motorbike POWER BATTERY PACK
Writer: Leonard Role: manufacturing leader
After Covid-19, people wanted to go outdoors more and be in touch with nature. Furthermore, with the urgency of climate change, EU policy has made green practices, environmental protection, and sustainable development a priority. Standards for auto vehicle exhaust emissions ihave also been raised. Hence, the trend towards development and adoption of electric vehicles is unavoidable. According to statistics, 26 out of 27 EU members have new policy in place to encourage electric cars transportation for environmental protection. Due to this, the market has a huge potential
About customer:
Our customer, MAEVING, also closely follow the policy and launched the RM1 electric motorcycle. They are a professional hand-made lightweight motorcycle company founded in 2018 by a team responsible for some of the greatest motorcycles in the UK, and have over a century of experience in British motorcycle engineering technology。
As a industrial manufacturing company, what can GREFEE do for this type of startup company, MAEVING has already designed the motorcycle drawing sheet during covid, , however, they spent nearly half a year to raise the capital for the first product prototype. Grefee also developed step by step from the initial few people to its current scale, which deeply impressed us. Therefore, our quotation for start-up companies is very friendly.
In terms of design：
Our engineering team can provide free manufacturability suggestions (DFM) for your product
In terms of materials:
Our engineers have extensive experience and can provide suitable material solutions based on your product
In terms of structure：
Our engineers will optimize structures that are not conducive to production to reduce manufacturing and production costs
In terms of production:
We do not have a minimum order quantity, and we will provide suitable production methods based on the customer’s quantity requirements
Regarding payment:
We have flexible payment terms and can accept a minimum deposit of 20%
Applied processes: injection molding, extrusion, die-casting, compression molding, stamping
Post processing applied: powder coating, sandblasting 120 , anodizing, texturing, anodizing.
Materials used: PC/ABC PC NBR 70 ° A380 TPE PVC AL6063 T2 Copper EVA
In 2023, we received an order from the ALEXANDER battery company, the cooperate partner of MAEVING about producing the battery for the electrical motorcycle, Includes one set of extrusion molds, six sets of injection molds, one set of silicone molds, and one set of die-casting molds. The whole plastic parts all adopted fire-proof material and the outer shell all utilized the reinforced alloy AL6063 that allows heat treatment, and the outer surface has been sandblasted with 120 grit. The handle all made of aluminum alloy A380, and this product requires 240 hrs Salt spray corrosion resistance test .
Preliminary work
The mold performance largely depends on the design maturity and our designers have been the determine factor for our mold quality. Through closely cooperating with the customers, the product can achieve a reasonable state at the designing stage and also saves time for manufacturing. Our designing team has over 15 years of experience in designing customized molds and we also provide a comprehensive designing program to achieve the profit maximization during the mold production and also guarantee the maintenance afterwards
EVALUATION OF THE PLASTIC PRODUCT
We have divided the product into two parts: appearance part and structural part. The former mainly focuses on whether the wall thickness is uniform and if there is any shrink that may affect the appearance. While, for interior parts, we more focused on whether the structure is reasonable and whether there is space for optimization to reduce the difficulties of production. Increasing the production efficiency and reducing the mold cost in the mean time
Assembly interference issue 1:
The first thing we did was checking the product assembly and we must guarantee that the product met the assembly requirements on the first mold trial. According to the showing picture below, we can see that the screw hole is 3.2 and the screw is M3.5. We brought out two recommendations which were step 1. increase the size of the screw through hole directly from 3.2 to 4.0. and step 2.modify the screw from a regular screw to an anti drop screw to achieve screw hole compatibility.
Assembly interference issue 2:
There is a 0.65 interference between the breathable valve and main body holes because this will result in the breathable valve not being able to be pressed to the bottom during assembly, thus failing to achieve a sealing effect. We suggest that customers reduce the material on the product surface and let the breathable valve go as low as possible to achieve a snug fit with the main body
Breathable Valve：
In China, breathable valves in different types and materials have standard parts already. Therefore, we recommended customers to cancel the separate production of the breathable valve to save the cost on the mold and production.
The material and types vary from the requirements. Usually, standard breathable valves are chosen, but we also have five major categories of products: plastic waterproof breathable valves, metal waterproof breathable valves, waterproof breathable explosion-proof valves, waterproof breathable plugs, and waterproof breathable integrated joints. There are many installation methods available, including threaded, snap on, and adhesive backed types. In addition, we also provide customized breathable valves service.
Product optimization：
The left and right conductive copper sheets are coated with PVC fire-resistant material. As the PVC material covers the straight surface of the product, additional structures need to be added to the mold for regular production. we have raised this issue with the customer and received confirmation. Although it is only a small modification, it can save customers about $2000 in mold manufacturing costs
Product optimization – Stamping
Sharp corners should be avoided on stamping parts on the product and extending the mold life in design. We recommend maintaining an R angle of at least R0.3 at the sharp corners of the product, and avoiding other features as much as possible at the bottom position where a 90 degree bend is required. When features are necessary, we recommend that they be at least 3mm parallel distance to the bending surface to ensure that the product’s features are not affected during the second processing.
Shell Extrusion Design:
The design of the extrusion product is mainly focused on uniform wall thickness as too big an error here will lead to uneven flow velocity and uneven cooling at the same time, which will cause deformation and size deviation, etc. Our extrusion engineer has been involved in the project since the designing stage so that many designing problems can be avoided and the research and development efficiency is much improved as well.
Post extrusion treatment of shell:
The shell, as the first protective layer of the battery, must have a certain degree of hardness and also should be acid resistant and alkali resistant. After anodizing, powder coating can meet these requirements well, and powder coating can also provide multiple color option. Its adhesion, uniformity, and weather resistance can make the color of the product smoother and more uniform.
Production Optimization -Injection Molding
As most of the copper plate is covered by the PVC material, only a small part of copper can be used to locate whether it is well centered. Therefore, we added fixation points in the central areas of the product to ensure that the copper plate will not be deviated during injection molding and to ensure uniform coating of PVC materia.
Stamping Production：
This battery set consists of 126 18650 lithium batteries, and the battery is connected with 16 0.3mm copper plates which have been stamped. The raw material that connects the battery and copper plate is T2 Purple Copper. After stamping, nickel plating (3-5um) is applied to the surface of the copper sheet. After the nickel plating, the copper sheet has better corrosion resistance and extends its service life
Aluminum Stamping：
The upper and lower layers of the battery are separated by 2mm aluminum pieces,which are made of 6060 soft aluminum plate, once again made by stamping technology. The aluminum plate is first cut for internal features, and then the side is bent by stamping. Because the internal R angle of the bending position is 1mm, bending may cause cracks on the back of the aluminum plate. Therefore, when bending, the bending position needs to be heated first before bending.
Die Casting Mold：
To create a better feel and look for the handle, the surface of the product needs to be brushed and polished. At the same time, it also requires to powder coat the surface of the product. On top of that, it also needs to withstand 240 hours salt spray corrosion resistance. These are contradicting surface requirements as the powder spray will cover the surface brushing or polishing effect. If the powder spray is not being done, the product will not have the capacity to withstand the 240hrs salt spray corrosion resistance test. After discussing with our customer, we came to the decision of removing the salt spray corrosion requirement in order to give priority for the appearance and the feel of the handle, which was deemed most important.
EVA Fire Proof Foam：
To better protect the interior battery set, the EVA fire proof foam and insulating Gasket have been added surrounding the bracket. Through adhering to the insulation paper, the foam can reduce the impact of vibration. The insulation paper is a type of durable, flexible and light weight electrical gas insulation substance with excellent heat resistance, which can withstand high temperatures of 130 degrees Celsius and a voltage of 4000V, while also having good corrosion resistance; Due to its excellent performance, insulating paper is widely used in the electronics industry.
Assembly Display
Assembly is the best test to verify the product. Grefee has produced 37 different types of products for this series, including injection molding, die-casting, stamping, compression molding and die cutting other processes , and the fully automatic adhesive bonding of EVA foam is required internally to prevent dust. As the interior must be dust free so all the processes must be undergone in a dust free workshop. We have 4 modern assembly lines that can achieve thousands of sets production capacity daily
Product Test:
According to using environment, we did rust and water proof tests on this series of products. As the breathable valve of lid is standard part so we need to test it, too. In addition, The interior bracket of the battery must be flame retardant material. We will test the brackets according to the UL94 testing standard. For products with fire protection requirements, the on-site fire testing of materials during trial molding and production is necessary to verify whether the flame retardant performance of the materials has been achieved, while also eliminating the problem of using the wrong materials.
Material Report：
As the foundation of quality, raw material is the key for us to win customers. We require that all the material suppliers must provide certificate, physical property table, certificate of origin, and material batch number. Our IQC will verify each batch of materials regularly. If necessary, we can also provide third-party testing reports.
Certification Certificate
Mold Display
We have many advantages in manufacturing products with multiple processes. GREFEE, as a comprehensive industrial manufacturing company, our mold department, production department,and assembly department work closely together and our engineers from each department make efforts together to contribute to product development and production.We can make products efficiently and at a high quality.
