Serial Multi-Battery Charger with Independent Simultaneous Charge and Discharge

• US 20150380959A1
• Filed: 06/26/2014
• Published: 12/31/2015
• Est. Priority Date: 06/26/2014
• Status: Active Grant

• Current Assignee: Hong Kong Applied Science And Technology Research Institute Co., Ltd.
• Original Assignee: Hong Kong Applied Science And Technology Research Institute Co., Ltd.
• Inventors: NG, Chik Wai (David), KWONG, Kwok Kuen (David), CHANG, Po Wah, TSANG, Chi Chiu, XU, Yuanzhe, OR, Wai Kei
• Granted Patent: US 9,385,542 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01M 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• CPC Class Codes: H01M 10/441 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/465 with solar battery as charging system
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits
• CPC Class Codes: H02J 7/0019 using switched or multiplexed charge circuits
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence
• CPC Class Codes: H02J 7/0045 concerning the insertion or the connection of the batteries
• CPC Class Codes: H02J 7/0068 Battery or charger load switching, e.g. concurrent charging and load supply H02J7/0013 takes precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 90/12 Electric charging stations

Abstract

A serial battery charger has a battery matrix with switches that are configured by a microcontroller that reads voltages between batteries to determine if each battery is fully-charged, charging, or absent. A switch configuration allows charging and discharging currents to flow simultaneously, and allows discharging current but blocks charging current from fully-charged batteries to prevent over-charging. The charging current flows through all charging batteries in series while the discharging current flows from all fully-charged and charging batteries in series. Blocking and bypass switches route the charging current to all charging batteries in series, but bypass all fully-charged and absent batteries. The blocking and bypass switches route the discharging current serially through all fully-charged and charging batteries in the battery matrix while avoiding absent batteries. The switches are controlled by the switch configuration from the microcontroller. Larger battery matrixes have row and column lines that are connected by connecting switches.

Claims

1. A switched battery matrix comprising:

a plurality of battery slots, each battery slot for accepting a battery, the battery slot having a positive terminal for connecting to a positive terminal of the battery, and a negative terminal for connecting to a negative terminal of the battery;

a plurality of row lines including positive row lines and negative row lines, wherein each battery slot has a positive terminal connected to a positive row line and a negative terminal connected to a negative row line;

a plurality of column lines;

a plurality of connecting switches, each connecting switch being coupled between a row line and a column line and allowing current to flow between the row line and the column line when the connecting switch is closed, but blocking current flow between the row line and the column line when the connecting switch is open;

a D+ column line in the plurality of column lines, the D+ column line connecting to a first discharge terminal;

a D−

column line in the plurality of column lines, the D−

column line connecting to a second discharge terminal;

wherein the plurality of connecting switches are configured to allow a discharge current to flow between the first and second discharge terminals, wherein the discharge current flows serially through all of the batteries in a charging state and all of the batteries in an over-charge-protected state that are installed in the plurality of battery slots;

a C+ terminal that receives a charging current from an external charging current source;

a C−

terminal that returns the charging current to the external charging current source after the charging current flows through all of the batteries in a charging state and none of the batteries in the over-charge-protected state that are installed in the plurality of battery slots; and

a plurality of distribution switches for connecting the C+ terminal to one of the plurality of column lines, and for connecting the C−

terminal to another one of the plurality of column lines;

wherein the plurality of distribution switches and the plurality of connecting switches are configured to allow both the charging current and the discharge current to flow simultaneously, wherein the charging current flows through all of the batteries in the charging state in series and through none of the batteries in the over-charge-protected state, and wherein the discharge current flows through all of the batteries in the charging state and all of the batteries in the over-charge-protected state in series,

whereby simultaneous charging and discharging of batteries occurs using a same configuration of switches.

2. The switched battery matrix of claim 1 wherein the plurality of column lines comprises at least 3 column lines and the plurality of row lines comprises at least 3 positive row lines and at least 3 negative row lines.

3. The switched battery matrix of claim 2 wherein the plurality of battery slots further comprises at least 3 battery slots.

4. The switched battery matrix of claim 1 further comprising:

a microcontroller for reading voltages of row lines or voltages of column lines to determine when a battery installed in a battery slot is in the charging state, the over-charge-protected state, or when no battery is installed in the battery slot, indicating an absent state.

5. The switched battery matrix of claim 4 wherein the microcontroller controls the plurality of connecting switches and the plurality of distribution switches to configure the connecting switches to allow the charging current and the discharge current to flow simultaneously.

6. The switched battery matrix of claim 5 wherein the plurality of distribution switches further comprise:

a plurality of blocking switches, each blocking switch for blocking the charging current from flowing between a manifold node and a column line in the plurality of column lines when the blocking switch is open, and for allowing the charging current to flow between the manifold node and the column line when the blocking switch is closed.

7. The switched battery matrix of claim 6 wherein the plurality of distribution switches further comprise:

a plurality of bypass switches coupled between a plurality of the manifold node, each bypass switch allowing the charging current to flow when the bypass switch is closed and preventing the charging current from flowing when the bypass switch is open;

wherein the C+ terminal is connected to a first node in the plurality of the manifold node, and the C−

terminal is connected to a last node in the plurality of the manifold node.

8. The switched battery matrix of claim 5 wherein each of the configuration switches comprises an n-channel transistor having a gate controlled by a signal from the microcontroller.

9. A serial battery charger comprising:

a first power manager that generates a charging current from a power source, the charging current flowing into a first charging terminal and returning from a second charging terminal;

a second power manager that receives a discharging current, the discharging current flowing from a first discharging terminal, through the second power manager and a load, and returning to a second discharging terminal;

a battery matrix having a first battery slot and a second battery slot each for receiving a battery, the battery being in a charging state when a voltage across the battery is less than a maximum voltage, the battery being in an over-charge-protected state when the voltage across the battery exceeds the maximum voltage, the battery being in an absent state when the battery is not present in the battery slot;

a microcontroller that reads voltages within the battery matrix to determine when the voltage across the battery exceeds or is less than the maximum voltage, the microcontroller determining states of batteries in the battery matrix and generating a switch configuration based on the states of the batteries;

a plurality of switches in the battery matrix, the plurality of switches being controlled by the switch configuration generated by the microcontroller,

wherein the microcontroller generates the switch configuration to configure the plurality of switches to allow the discharging current to flow between the first and second discharging terminals, wherein the discharging current flows serially through all of the batteries in the charging state and all of the batteries in the over-charge-protected state that are installed in the battery matrix;

wherein the switch configuration also configures the plurality of switches to allow the charging current to flow between the first and second charging terminals, wherein the charging current flows serially through all of the batteries in the charging state and none of the batteries in the over-charge-protected state and none of the batteries in the absent state in the battery matrix;

wherein the switch configuration allows the charging current and the discharging current to flow simultaneously while blocking the charging current from the batteries in the over-charge-protected state.

10. The serial battery charger of claim 9 wherein the battery matrix comprises:

a first battery in a first battery slot;

a second battery in a second battery slot;

an intermediate node between a negative terminal of the first battery and a positive terminal of the second battery;

wherein a positive terminal of the first battery is connected to the first discharging terminal;

wherein a negative terminal of the second battery is connected to the second discharging terminal,

whereby the first battery and the second battery are connected in series between the first discharging terminal and the second discharging terminal.

11. The serial battery charger of claim 10 wherein the plurality of switches in the battery matrix comprises:

a first switch coupled to conduct current between the first discharging terminal and the first charging terminal;

a second switch coupled to conduct current between the first charging terminal and the intermediate node;

a third switch coupled to conduct current between the intermediate node and the second charging terminal; and

a fourth switch coupled to conduct current between the second charging terminal and the second discharging terminal.

12. The serial battery charger of claim 11 wherein the microcontroller generates the switch configuration to open the first switch and prevent current flow between the first discharging terminal and the first charging terminal when the first battery is absent or in the over-charge-protected state;

wherein the microcontroller generates the switch configuration to open the fourth switch and prevent current flow between the second discharging terminal and the second charging terminal when the second battery is absent or in the over-charge-protected state;

wherein the microcontroller generates the switch configuration to close the second switch and conduct current flow between the first charging terminal and the intermediate node when the second battery is in the charging state and the first battery is absent or in the over-charge-protected state;

wherein the microcontroller generates the switch configuration to close the third switch and conduct current flow between the intermediate node and the second discharging terminal when the first battery is in the charging state and the second battery is absent or in the over-charge-protected state.

13. The serial battery charger of claim 12 wherein the microcontroller executes a battery status routine which comprises:

reading a first voltage of the first discharging terminal;

when the first voltage is at least twice a maximum voltage of a fully-charged battery, indicating that the first battery is in the over-charge-protected state and indicating that the second battery is in the over-charge-protected state;

reading a second voltage of the intermediate node;

when a voltage across the first battery is less than the maximum voltage, indicating that the first battery is in the charging state;

when the second voltage is less than the maximum voltage, and indicating that the second battery is in the charging state; and

when the second voltage meets or exceeds the maximum voltage, and indicating that the second battery is in the over-charge-protected state.

14. The serial battery charger of claim 9 wherein the battery matrix comprises three batteries in series;

wherein each battery slot comprises a positive terminal for connecting to a positive terminal of the battery, and a negative terminal for connecting to a negative terminal of the battery;

further comprising;

a plurality of row lines including positive row lines and negative row lines, wherein each battery slot has a positive terminal connected to a positive row line and a negative terminal connected to a negative row line;

a plurality of column lines;

wherein the plurality of switches further comprises;

a plurality of connecting switches, each connecting switch being coupled between a row line and a column line and allowing current to flow between the row line and the column line when the connecting switch is closed, but blocking current flow between the row line and the column line when the connecting switch is open.

15. A multiple battery charger comprising:

a plurality of battery slots, each battery slot for accepting a battery;

a plurality of blocking switches, each blocking switch being in series with a battery slot in the plurality of battery slots;

a plurality of bypass switches, each bypass switch being in parallel with a battery slot in the plurality of battery slots;

a charging current generator that uses a power source to generate a charging current that flows into a first charging node, in series through a plurality of charging batteries installed in the plurality of battery slots, and returning through a second charging node;

a discharging current load that receives from a first discharging node a discharging current generated by the plurality of charging batteries and by a plurality of fully-charged batteries installed in the plurality of battery slots, and returns to the plurality of battery slots through a second discharging node;

wherein the discharging current is routed in series through each battery of the fully-charged and charging batteries installed in the plurality of battery slots;

a microcontroller that reads a first voltage of the first discharging node, and at least one intermediate voltage of an intermediate node between batteries, the microcontroller selecting a switch configuration based on voltages read, the switch configuration generating control signals to control the plurality of blocking switches and the plurality of bypass switches to route the charging current to all charging batteries and to none of the fully-charged batteries and to none of the plurality of battery slots missing a battery, and to route the discharging current to all charging batteries and to all of the fully-charged batteries in series and to none of the plurality of battery slots missing a battery;

wherein the charging current and the discharging current flow at a same time, sharing at least some switches in the plurality of bypass switches and in the plurality of blocking switches;

wherein the charging current is routed to charging batteries and bypassed around fully-charged batteries while the discharging current is routed to charging batteries and fully-charged batteries,

whereby simultaneous charging and discharging currents flow serially through batteries.

16. The multiple battery charger of claim 15 wherein the charging current flows without a diode voltage drop due to a diode in a path of the charging current;

wherein the discharging current flows without a diode voltage drop due to a diode in a path of the discharging current;

whereby diode voltage drops are avoided.

17. The multiple battery charger of claim 15 further comprising:

a first battery in a first battery slot;

a second battery in a second battery slot;

wherein the intermediate node is between a negative terminal of the first battery and a positive terminal of the second battery;

wherein a positive terminal of the first battery is connected to the first discharging node;

wherein a negative terminal of the second battery is connected to the second discharging node,

whereby the first battery and the second battery are connected in series between the first discharging node and the second discharging node.

18. The multiple battery charger of claim 17 wherein the plurality of blocking switches comprises:

a first switch coupled to conduct current between the first discharging node and the first charging node;

a fourth switch coupled to conduct current between the second charging node and the second discharging node;

wherein the plurality of bypass switches comprises;

a second switch coupled to conduct current between the first charging node and the intermediate node; and

a third switch coupled to conduct current between the intermediate node and the second charging node.

19. The multiple battery charger of claim 18 wherein the microcontroller generates the switch configuration to open the first switch and prevent current flow between the first discharging node and the first charging node when the first battery is absent or is fully-charged;

wherein the microcontroller generates the switch configuration to open the fourth switch and prevent current flow between the second discharging node and the second charging node when the second battery is absent or fully-charged;

wherein the microcontroller generates the switch configuration to close the second switch and conduct current flow between the first charging node and the intermediate node when the second battery is charging and the first battery is absent or is fully-charged;

wherein the microcontroller generates the switch configuration to close the third switch and conduct current flow between the intermediate node and the second discharging node when the first battery is charging and the second battery is absent or fully-charged.

20. The multiple battery charger of claim 19 wherein the first switch, the second switch, the third switch, and the fourth switch each comprise a power metal-oxide-semiconductor field-effect transistor (MOSFET).