Battery Pack Switching Control Against Parallel Cross Currents
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The parallel connection of battery packs in electric vehicles leads to a decrease in the upper limit value of current or power supplied to the load, causing adverse effects such as degradation in acceleration performance due to cross currents.
Innovation Solution
A management device that determines the state of switches connected to power storage modules, ensuring that only those with an upper limit value of current or power greater than or equal to the pre-connection value are turned on, preventing the connection of unconnected battery packs that would reduce the discharge upper limit current or power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If battery packs are connected in parallel to increase current supply capacity, then the number of power storage modules increases, but cross currents are generated causing the upper limit value of current or power to decrease
Solution Approach 1:
The management device performs preliminary determination of the upper limit value of current or power before actually connecting power storage modules in parallel. By predicting the upper limit value in advance based on the determination unit's calculation, the system can identify whether adding more modules will result in cross currents that reduce the overall power supply capacity, thus preventing harmful connections before they occur.
Solution Approach 2:
The control unit uses feedback from the determination unit's calculation of the upper limit value to control the connection of power storage modules. The system continuously monitors and adjusts the connection state based on the predicted upper limit value, ensuring that parallel connections only occur when they will maintain or increase the current supply capacity without generating harmful cross currents.
2Productivity
If more power storage modules are connected in parallel, then the current supply capacity should increase, but cross currents reduce the upper limit value below pre-connection levels
Solution Approach 1:
The management device performs preliminary determination of the upper limit value of current or power before actually connecting power storage modules in parallel. By predicting the upper limit value in advance based on the determination unit's calculation, the system can identify whether adding more modules will result in cross currents that reduce the overall power supply capacity, thus preventing harmful connections before they occur.
Solution Approach 2:
The control unit uses feedback from the determination unit's calculation of the upper limit value to control the connection of power storage modules. The system continuously monitors and adjusts the connection state based on the predicted upper limit value, ensuring that parallel connections only occur when they will maintain or increase the current supply capacity without generating harmful cross currents.
Data Source
AI summary
Management device manages a plurality of power storage modules connected in parallel to load via switches. With some of switches connected to some of the plurality of power storage modules being in an on state and other switches connected to other power storage modules being in an off state, determination unit of management device does not permit at least one of other switches in the off state to be turned on in a case where at least one switch is turned on and an upper limit value of a current or power allowed to be supplied to load entirely from the plurality of power storage modules with at least one switch being turned on becomes less than or equal to a value before the turning-on of at least one switch.