Senior Mechanical Design Engineer

Job Title: Senior Mechanical Design Engineer Location: Peterlee Salary: £45,000 - £50,000 per annum (Depending on experience) Job type: Full time, Permanent Working Hours: 37.5 hours per week - 08:30-17:00 M-T and 08:30-14:00 F We are seeking an experienced Senior Mechanical Design Engineer to join our growing engineering team in Peterlee. The successful candidate will take technical ownership of mechanical design for advanced battery pack assemblies, leading the full design cycle from concept to production release. This role requires a solid foundation in SolidWorks, plastic injection moulded component design, and thermoplastic material selection, combined with a strong understanding of design for manufacture (DFM) and design for assembly (DFA) principles. You will play a key part in the development of innovative, robust, and cost-effective mechanical solutions for battery systems used across demanding industrial, automotive, and mobility applications. The role includes technical mentoring and day-to-day management of two junior design engineers. Main Duties and Responsibilities Lead the mechanical design and development of custom lithium-based battery systems, including enclosures, structural housings, interconnects, cooling components, and mounting solutions. Design injection-moulded plastic components and metal fabricated parts, ensuring manufacturability, dimensional stability, and compliance with industry standards. Apply sound engineering judgement in material selection, wall thickness, draft angle, ribs and bosses, tolerancing, and tooling considerations for thermoplastic and metal components. Oversee the creation of detailed 3D CAD models and 2D engineering drawings in SolidWorks, including GD&T and BOM control. Support design validation and prototype testing, liaising with suppliers, tooling partners, and internal manufacturing teams. Work closely with electrical and electronics engineers to ensure seamless integration of BMS, PCBs, harnesses, and connectors within mechanical designs. Manage design reviews, track project deliverables, and maintain engineering documentation within the company's ERP system. Provide technical leadership and mentorship to two junior engineers, supporting their professional development and ensuring consistent design quality. Contribute to continuous improvement of design processes, materials selection, and manufacturing practices. Knowledge, Skills and Behaviours Degree (BEng or higher) in Mechanical Engineering, Product Design Engineering, or a related discipline. Equivalent professional experience will be considered in lieu of formal qualifications. Minimum of 5 years' experience in mechanical design within a product development or manufacturing environment. Proficient in SolidWorks, including surfacing, assemblies, configuration management, and drawing creation. Proven experience with plastic injection moulded component design, including DFM/DFA, draft analysis, and tooling liaison. Knowledge of thermoplastic materials (e.g., PC, ABS, PA6, PBT, PC+ABS, PPS, etc.) and their behaviour in demanding environments. Experience with metal component design (sheet metal, machined, cast, or formed parts) and basic tolerance stack‑up analysis. Familiarity with electro‑mechanical assemblies and packaging of electrical/electronic systems such as PCBs, harnesses, and sensors. Competent in geometric dimensioning and tolerancing (GD&T), finite element analysis (FEA), and design validation testing. Strong appreciation for IP sealing, thermal management, and EMC considerations in enclosure design. Excellent organisational skills with the ability to manage multiple projects and priorities. Strong communication and interpersonal skills for collaboration across engineering, purchasing, and production teams. Experience within the battery, energy storage, automotive, or electro‑mechanical systems sectors. Working knowledge of compliance standards such as UN 38.3, IEC 62133, UL 2271, or related mechanical/environmental test methods. Exposure to tooling design review, supplier management, and manufacturing support. Basic understanding of electrical schematics or PCB layouts. Demonstrated ability to lead a small team and drive projects to completion within defined timelines. Additional Notes Candidates must be authorised to work in the UK and work onsite from our offices based in Peterlee. We kindly ask that recruitment agencies refrain from contacting us regarding this vacancy. Any unsolicited CVs submitted will be treated as having been provided free of charge, with no agency fees applicable. Please click the APPLY button to submit your CV for this role. Candidates with experience or relevant job titles of; Senior Mechanical Design Engineer, Mechanical Engineer, Senior Mechanical Design Engineer, Project Design Engineer, Mechanical Engineering, Manufacturing Engineer may also be considered for this role. #J-18808-Ljbffr