Research on the Brake-by-Wire Industry - 南京市创新投资集团有限责任公司

If you have further insights and thoughts on this article, please contact the author: Guo Shaobin, Investment Department II, Nanjing Innovation Investment GroupE-mail: guoshaobin@njicg.com

With the global wave of automotive electrification and intelligence, high-level autonomous driving at L3 and above has become the core battlefield for automakers’ competition. The brake-by-wire chassis, the core foundation supporting this transformation, converts the five key systems of traditional chassis—braking, throttle, steering, shifting and suspension—from mechanical hard connections to electronic signal control through drive-by-wire technology. It enables precise coordinated execution of acceleration, braking, steering and other functions, serving as the core execution layer in the "perception-decision-execution" closed loop of intelligent vehicles.

As a key component to ensure driving safety, brake-by-wire not only adapts to the power structure of new energy vehicles, but also becomes a "standard configuration" for the implementation of high-level autonomous driving with millisecond-level response speed, nurturing a hundred-billion-yuan market opportunity.

I. Overview of Brake-by-Wire Chassis

Chart: Schematic Diagram of Brake-by-Wire Chassis

1. Core Definition and Technical Architecture

The core value of the brake-by-wire chassis lies in meeting the stringent requirements of L3 and above high-level autonomous driving for response speed (millisecond level), control precision and functional coordination. Its technical architecture includes three layers: "perception, decision and execution".

Perception Layer: Acquires road conditions and vehicle status through millimeter-wave radar, lidar, high-definition cameras, integrated inertial navigation, 4G/5G positioning, ADAS/high-precision maps, etc.
Decision Layer: The autonomous driving domain controller (ADC) and chassis domain controller (CDCU) complete perception fusion, navigation and positioning, decision planning and control command output.
Execution Layer: Realizes dynamic control of the vehicle's XYZ three-direction and six-degree-of-freedom through five subsystems: steer-by-wire, brake-by-wire, active suspension, shift-by-wire and drive-by-wire.

2. Development Stage: 2020-2030

3. Core Trends: Domain Control Integration and Cross-Domain Collaboration

Intra-domain Integration: By improving the integration of subsystems, it realizes coordinated control of XYZ three-direction and six-degree-of-freedom, optimizing the vehicle's dynamic performance such as lateral stability, vibration attenuation capability and steering flexibility.
Cross-domain Integration: Breaks the boundaries between the chassis domain and the autonomous driving domain, cockpit domain and body domain, and promotes the linkage of vehicle intelligent functions. For example, the in-depth coordination between the braking system and the AEB (Autonomous Emergency Braking) and ACC (Adaptive Cruise Control) functions of the autonomous driving domain.
Technology Evolution: Upgrades from "electromechanical hybrid" to "full drive-by-wire". Chassis control evolves from distributed ECU to chassis domain control and power-chassis fusion control, and finally moves towards central domain control integration, simplifying the electronic and electrical architecture, reducing wiring harness costs and improving data transmission efficiency.

4. Evolution Path of Domain Control Technology

II. Technology Iteration and Market Analysis of Brake-by-Wire

1. Core Definition and Core Value

Brake-by-wire is a revolutionary technology that realizes braking control through electronic signals instead of mechanical connections. Its working process is as follows:

The brake pedal position sensor captures the driver's intention and converts it into an electronic signal;
The electronic control unit (ECU) receives the signal and calculates the optimal braking force;
The drive actuator (hydraulic or electric motor) generates braking force, and feeds back the pedal feel through algorithms.

The core value is reflected in three aspects:

Adaptation to New Energy Vehicles: Gets rid of the dependence on vacuum source and solves the pain point of electric vehicles without engine vacuum assistance.
Support for Autonomous Driving: The response speed is increased by more than 30% compared with traditional braking, and some products are ≤90ms, meeting the precise control requirements of high-level autonomous driving for the execution end.
Energy Saving and High Efficiency: Decouples braking and energy recovery, which can increase the cruising range of electric vehicles by 5%-10%.

2. Technical Routes: EHB Leads the Present, EMB Leads the Future

The technological evolution of brake-by-wire presents a clear path of "Electro-Hydraulic Brake (EHB) → Electro-Mechanical Brake (EMB)". The two core routes run in parallel, and derive One-box and Two-box subdivision solutions.

(1) Electro-Hydraulic Brake (EHB): Current Mainstream of the Market (80% Market Share)

Retains hydraulic pipelines and integrates ABS/ESC units, divided into two schemes:

Data Source: Public Information Collection, GGAI, Zos Auto, Guotai Haitong Securities

(2) Electro-Mechanical Brake (EMB)

Completely abandons the hydraulic system and directly drives the brake caliper through 4 wheel-end motors to achieve "full drive-by-wire", known as "dry" brake-by-wire. Its core advantages and technical difficulties are as follows:① Core Advantages:

Shorter response speed: 80ms vs 150ms of EHB, close to the limit of human nerve reflex;
More streamlined system: Eliminates hydraulic pipelines, brake fluid and booster, reducing vehicle assembly and maintenance costs by more than 30%;
Better performance: Zero drag (improves cruising range), lower noise (far from the cockpit) and lighter weight;
Higher integration: Can integrate parking (EPB) and driving braking functions, reducing assembly processes by 1-2 steps.

② Technical Difficulties:

Safety Redundancy: Needs to meet ASIL-D level safety requirements, solve the problems of thermal management of wheel-side motors and high-temperature recession resistance of permanent magnets, and realize "dual-circuit redundancy";
Durability: Needs to pass 2.2 million fatigue durability tests with a service life of about 2300 hours;
Core Components: Wheel-side motors need to operate stably in extreme cold of -40℃ to high temperature of 120℃ and strong vibration environment. Gearboxes need to withstand greater torque, and ball screws need to be used instead of traditional thread transmission;
Cost Control: The current system cost is 1.4-3 times that of traditional hydraulic systems, and it is expected to be equal to the cost of hydraulic systems in 2026.

(3) Electronic Parking Brake (EPB): Pioneer Application of Drive-by-Wire Technology

EPB (Electronic Parking Brake) is the implementation of brake-by-wire in the parking system, which has achieved front-loading standard configuration (penetration rate exceeded 90% in 2023), divided into:

Independent Type: Equipped with a separate EPB ECU with high cost;
Integrated Type: Integrates EPB and ESC into one controller, reducing ECU cost and wiring harness complexity. Enterprises need to have ESC production capacity or cooperate with ESC suppliers. Most domestic manufacturers rely on international ESC suppliers.

3. Industrial Chain Panorama: From Core Components to Terminal Applications

(1) Industrial Chain Structure

Upstream: EHB/EMB general components (solenoid valves, PCBs, automotive-grade MCU chips), brake motors (permanent magnet DC brushless motors, permanent magnet synchronous motors), sensors (pressure/temperature/wheel speed/steering angle sensors), brakes (caliper, brake disc);
Midstream: Brake-by-wire system integrators (foreign Tier 1, domestic listed companies, start-ups);
Downstream: Passenger vehicles, commercial vehicles, special vehicles, and automotive aftermarket.

(2) Upstream Core Links and Representative Enterprises

Data Source: Public Information Collection

(3) Competition Pattern of Midstream System Integrators

Foreign capital dominates but domestic substitution accelerates: In H1 2024, Bosch's market share was 53.68%, down from 68.72% in 2022; Continental Group accounted for 23%; domestic suppliers accounted for 32.57% in total.

EHB Market: Foreign leaders include Bosch (iBooster/IPB) and Continental (MKC1); domestic enterprises such as Bethel Automotive Safety Systems, Fudi Power, Liketech, and Nasen Technology have ranked among the top ten.
EMB Market: Overseas companies such as Brembo and Bosch plan mass production in 2025; domestic enterprises such as Bethel, Liketech, Tongyu Electronics, Coordinate System, Gelubo, and Jingxi are accelerating their layout.

4. Market Scale: Hundred-Billion-Yuan Track Expands Rapidly

(1) EHB Market

Penetration Rate: In 2024, the assembly volume of brake-by-wire EHB exceeded 10 million units, a substantial year-on-year increase of 61.4%. From January to July 2025, the assembly volume of EHB was close to 6 million units, and it is expected that the annual assembly volume of EHB will exceed 12 million units in 2025. In terms of assembly rate, the annual assembly rate is expected to exceed 50% in 2025.
Market Size: Expected to exceed 20 billion yuan in 2025.

(2) EPB Market

In 2022, the front-loading standard configuration of domestic passenger vehicles was 16.7358 million units, with a penetration rate of over 80%;
The market size was 12 billion yuan in 2023 (passenger vehicles accounted for 85%), and it is expected to reach 18.3 billion yuan in 2025 with a penetration rate of 90%;
Competition Pattern: Bosch, Huayu Automotive Systems, Continental Group, Ningbo Huaxiang Electronics, etc.

(3) EMB Market (Mass Production First Year in 2026)

Key Assumptions: Annual passenger vehicle sales increase by 2%; brake-by-wire penetration rate is 60% in 2025/70% in 2030; EMB proportion is 1% in 2025/40% in 2030; EMB ASP is 2500 yuan in 2025/1681 yuan in 2030;
Market Size: Installation volume will increase from 140,000 sets in 2025 to 7.13 million sets in 2030, with a scale exceeding 10 billion yuan;
Penetration Rate: The penetration rate of new energy vehicles will exceed 15% in 2028, and the penetration rate of L3+ models will exceed 50% in 2030.

III. Investment Logic: Driving Factors and Core Opportunities

1. Core Driving Factors

(1) New Energy Vehicles Replace Fuel Vehicles, Spurring Upgrading of Braking Systems

Fuel vehicles generate vacuum through the engine intake manifold to provide assistance for hydraulic braking; new energy vehicles have no internal combustion engine, and electronic vacuum pumps have a short service life (2-3 years) and high maintenance costs, which cannot meet long-term use needs. Brake-by-wire replaces vacuum assistance with electronic assistance, perfectly solving the problem of vacuum source shortage in new energy vehicles. With the increase in the penetration rate of new energy vehicles, the configuration rate of brake-by-wire increases synchronously.

(2) Stringent Requirements of High-Level Autonomous Driving for the Execution End

L3 and above autonomous driving require the actuator to have fast response (≤150ms) and precise control (braking force error ±5%). The response time of traditional hydraulic braking is 200-300ms, which cannot meet the demand. The high response speed and high integration of brake-by-wire (EHB/EMB) have become the core support for the implementation of high-level autonomous driving.

(3) Policy and Regulatory Endorsement, Removing Obstacles for EMB Mass Production

The "GB21670-2025 Technical Requirements and Test Methods for Passenger Vehicle Braking Systems" issued on May 30, 2025, was implemented on January 1, 2026. It clearly defines ETBS (Electronic Control Braking System) at the regulatory level for the first time, classifies EMB as a subclass of ETBS, and provides a legal basis for EMB mass production. This standard refers to the UN UNR13-H regulation, promotes the integration of Chinese standards with international standards, and supports local enterprises to take the lead in mass-producing EMB globally.

(4) Rising Demand for Energy Recovery, Highlighting the Advantages of Brake-by-Wire

The battery cost of new energy vehicles accounts for 30%-40% of the whole vehicle, and energy recovery is the key to improving cruising range. Brake-by-wire realizes complete decoupling of brake pedal and braking force, can flexibly allocate the proportion of mechanical braking force and regenerative braking force, with a recovery efficiency of over 85%, an increase of 20%-30% compared with traditional braking, and can reduce battery capacity configuration by about 10%.

2. Core Investment Opportunities

(1) Accelerated Domestic Substitution, Continuous Increase in Market Share of Domestic Suppliers

The price reduction space of foreign suppliers such as Bosch and Continental is limited;Domestic suppliers have made breakthroughs in One-Box mass production (Bethel took the lead in mass production in 2021) and EMB R&D (Coordinate System, Huashen Ruili), with faster response speed (30% reduction in model development cycle) and higher coordination (customized services), which meet the demand of OEMs for independent and controllable supply chains;In H1 2024, the market share of domestic suppliers reached 32.57%, an increase of 12 percentage points compared with 2022, indicating broad space for domestic substitution.

(2) Technology Iteration Dividend: One-Box Leads the Present, EMB Layouts for the Future

One-Box: The penetration rate increased from 20.5% in 2021 to 65.1% in H1 2024, becoming the mainstream solution in the drive-by-wire market. Domestic enterprises such as Bethel, Liketech and Nasen Technology have achieved mass production;
EMB: The mass production first year in 2026 is approaching. Domestic enterprises have seized the technological high ground, which will trigger industry reshuffle in the next 3-5 years.

(3) Automakers' "Independent R&D + Co-R&D" Layout, Reconstructing the Supply Chain Ecosystem

Domestic OEMs have generally built independent and controllable supply chains. BYD (Fudi Technology), Great Wall Motor (Precision Chassis/Feige Technology), Chery (Bethel), SAIC (United Automotive Electronic Systems) and others have all laid out in the brake-by-wire field, which not only ensures the mass production of One-Box, but also makes forward-looking layout of EMB, providing stable orders for domestic suppliers.

(4) Segmented Track Opportunities: Domestic Substitution of Upstream Core Components

Automotive-Grade MCU Chips: Domestic enterprises such as CoreWise Microelectronics, CoreTitan Technology and Xpeedic Technology have achieved breakthroughs in ASIL-B/D level products, with substitution space exceeding 10 billion yuan;
Sensors: Foreign capital accounts for more than 70% of pressure sensors, IMU and other products. Enterprises such as Amperor Electronics and Navitas Semiconductor are accelerating import substitution;
Brake Calipers: The high-end market is monopolized by Brembo and Continental. Domestic enterprises such as Bethel and Yatai Co., Ltd. are accelerating their layout, with domestic substitution space exceeding 5 billion yuan.

Source: Guo Shaobin, Investment Department II

Reviewer: Xue Yao

Publisher: You Yi