Abstract:

With the rapid development of the electric vehicle （EV） industry， competition among original equipment manufacturers （OEMs） is intensifying. As a core component of EVs， the range of batteries affects the demand for electric vehicles. To ensure the supply of high-range batteries， many OEMs collaborate with battery suppliers on R&D. However， whether cooperation between vehicle manufacturers and suppliers can effectively improve battery range and thereby increase profits for both parties remain need to explore. In a supply chain consisting of a single battery supplier and two competing OEMs， considering customers’ sensitivity toward battery range， the optimal decisions of supply chain members when the supplier independently develops batteries are investigated. Next， the optimal decisions of the three parties are considered when manufacturer 1 collaborates with the supplier on battery R&D， while manufacturer 2 does not participate in the cooperation. Finally， the technology spillover effect is introduced when manufacturer 1 collaborates with the supplier and the impact of the technology spillover effect on the decisions of supply chain members is explored. The game sequence in the model is as follows： in the first stage， the battery supplier decides the range of batteries 1 and 2 to maximize its own profit； in the second stage， vehicle manufacturers 1 and 2 decide the EV prices to maximizing their own profits. The optimal battery range and electric vehicle prices under the three models are obtained using the backward induction method. Further， the impact of parameters such as customer sensitivity to battery range， price competition， and technology spillover effect on optimal decisions are analyzed， and the changes in optimal decisions and profits of supply chain members under the three scenarios are compared. Finally， through parameter simulation， numerical experiments are conducted. The main finding are： （1） cooperation on R&D does not necessarily lead to significant improvements in battery range， especially when manufacturers negotiate lower wholesale battery prices. In such cases， suppliers may lack the incentive to engage in cooperation， potentially resulting in non-participation or passive collaboration strategies； （2） technological spillover effects do not inherently enhance battery range in the absence of collaborative R&D. Their impact depends on key parameters such as the wholesale battery price， consumer sensitivity to driving range， and the intensity of price competition in the market； （3） for manufacturers engaged in collaborative R&D， greater investment in cooperation increases the likelihood of obtaining profits. However， as the technological spillover effect intensifies， manufacturers must invest more resources to ensure profitability from collaborative R&D； （4） collaborative R&D does not necessarily improve the profits of both the supplier and the two manufacturers. Nevertheless， within specific parameter regions， all three parties may benefit from technological spillovers.

Key words: battey range, vertical collaborative r&d, technology spillover effect, battery supplier, competitive EV manufacturers