Battery Pack Pulse Charging for Cell Imbalance Correction

Solution Overview

Problem

Battery packs with varying cell charge capacities lead to imbalanced charging and discharging, limiting their full capacity utilization and reducing energy efficiency, due to the need for complex and costly cell balancing techniques.

Innovation Solution

A method and system that employ a first charging protocol for battery packs, determining imbalances based on cell parameters, and switching to a second balancing-optimized pulse charging protocol with shorter pulses when the state of charge falls within a specific range, to balance voltage and capacity across cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional cell balancing techniques are used, then battery cell imbalance is corrected, but device complexity and cost increase significantly

Engineering Contradiction:

Improvebattery pack balanceVSAvoidcontrol circuitry complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies self-service by using the battery management system's existing charging control capabilities to automatically detect and correct cell imbalances during normal charging operations. The BMS monitors cell voltages and dynamically adjusts charging current distribution without requiring external balancing equipment, allowing the system to self-correct imbalances using its own resources.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent makes the charging circuitry multi-functional by enabling it to perform both primary charging and cell balancing functions. The same charging current control mechanisms used for charging the battery pack are also utilized to equalize cell voltages, eliminating the need for separate balancing circuitry and reducing overall system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If conventional cell balancing techniques are used, then battery cell imbalance is corrected, but manufacturing cost increases

Engineering Contradiction:

Improvebattery pack balanceVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent makes the charging circuitry multi-functional by enabling it to perform both primary charging and cell balancing functions. The same charging current control mechanisms used for charging the battery pack are also utilized to equalize cell voltages, eliminating the need for separate balancing circuitry and reducing overall system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent applies self-service by using the battery management system's existing charging control capabilities to automatically detect and correct cell imbalances during normal charging operations. The BMS monitors cell voltages and dynamically adjusts charging current distribution without requiring external balancing equipment, allowing the system to self-correct imbalances using its own resources.

Inventive Principle:

Principle #25Self-service

3Reliability

If charging stops at full charge of one cell, then cell imbalance is prevented, but battery pack capacity utilization decreases

Engineering Contradiction:

Improvecell charge limit safetyVSAvoidbattery pack capacity utilization

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent applies dynamics by transitioning from a static charging approach (uniform current to all cells) to a dynamic approach where charging current is continuously adjusted based on real-time cell voltage measurements. The BMS dynamically identifies which cells are closest to full charge and reduces or stops charging current to those specific cells while maintaining charging current to other cells that are not yet full, enabling continuous optimization of capacity utilization.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent applies local quality by treating each battery cell individually with customized charging current based on its specific charge state. Instead of applying uniform charging current to all cells, the system applies different charging currents to different cells based on their individual voltage levels and proximity to full charge, allowing each cell to be charged according to its local needs.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS11831186B2Balancing a battery pack with pulse charging

Publication Date: 2023.11.28 GBATTERIES ENERGY CANADA INC

AI summary

Disclosed are systems, methods, and devices for balancing a battery pack that comprises a plurality of battery cells. A first charging protocol to charge the battery pack is employed, and while the battery pack is being charged, a determination is made whether the battery pack is imbalanced. After determining that the battery pack is imbalanced, a determination is made whether a value of the state of charge (SoC) of the battery pack corresponds to a particular range of values. After determining that the value of the SoC of the battery pack corresponds to the particular range of values and that the battery pack is imbalanced, a second charging protocol to charge the battery pack is employed, wherein the second charging protocol is different from the first charging protocol.