# US 11,114,711 B2 · Rapid low-temperature self-heating method and device for battery

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- Number: US 11,114,711 B2
- Document ID: US11114711B2
- Status: Granted
- Kind: B2
- Application number: 16/732,660
- Filed: 2020-01-02
- Published: 2020-10-08
- Granted: 2021-09-07
- Earliest claimed: 2019-04-08
- Assignees: Beijing Institute of Technology
- Applicants: Beijing Institute of Technology
- Inventors: Rui Xiong; Zeyu Chen; Hongwen He; Fengchun Sun
- Web page: https://patentgrep.com/patent/US11114711B2

## CPC

- H01M 10/637: characterised by the use of reversible temperature-sensitive devices, e.g. NTC, PTC or bimetal devices; characterised by control of the internal current flowing through the cells, e.g. by switching (means for preventing undesired use or discharge H01M50/572)
- H05B 1/0236: {for vehicles}
- B60L 3/12: Recording operating variables {; Monitoring of operating variables}
- B60L 58/25: by controlling the electric load
- B60L 58/27: by heating
- H01M 10/48: Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte (constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569)
- H01M 10/486: {for measuring temperature}
- H01M 10/615: Heating or keeping warm
- H01M 10/625: Vehicles
- H01M 10/633: characterised by algorithms, flow charts, software details or the like
- H05B 3/0004: {Devices wherein the heating current flows through the material to be heated (Circuit arrangements for heating by passing the current directly across the material to be heated H05B3/0023; granular, powdered or fluid material H05B3/60)}
- H05B 3/0014: {Devices wherein the heating current flows through particular resistances}
- B60L 2240/545: Temperature
- B60L 2240/549: Current
- H01M 2010/4271: {Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing}
- H01M 2220/20: Batteries in motive systems, e.g. vehicle, ship, plane
- H05B 2203/035: Electrical circuits used in resistive heating apparatus
- Y02E 60/10: Energy storage using batteries
- Y02T 10/70: Energy storage systems for electromobility, e.g. batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- B60L: PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES (arrangements or mounting of electrical propulsion units or of plural diverse prime-movers for mutual or common propulsion in vehicles B60K1/00, B60K6/20; arrangements or mounting of electrical gearing in vehicles B60K17/12, B60K17/14; preventing wheel slip by reducing power in rail vehicles B61C15/08; dynamo-electric machines H02K; control or regulation of electric motors H02P); SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES (electric coupling devices combined with mechanical couplings of vehicles B60D1/64; electric heating for vehicles B60H1/00); ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL (control or regulation of electric motors H02P); MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

The present invention relates to a rapid low-temperature self-heating method and device for a battery. Active controllable large-current lossless short-circuit self-heating cooperates with an external heater to implement rapid composite heating, so that a battery is rapidly heated in a low-temperature environment and is controlled to fall within an optimal working temperature interval, so as to improve energy utilization of the battery and durability of a battery system. Before the battery system is started, battery temperature is first determined; when the temperature is less than a threshold, an external short-circuit is first proactively triggered to generate a large current to implement self-heating inside the battery. The method is simple, easy to implement, and safe and reliable, and can effectively resolve a problem that an electric vehicle has large capacity degradation and poor working performance in a low-temperature severe cold working condition.

## Claims

### Claim 1

A rapid low-temperature self-heating method for a battery, wherein a control method of a heating system specifically comprises the following steps:
triggering a large-current external short-circuit for rapid heating of the battery, recording short-circuit duration and a short-circuit current when the external short-circuit occurs on the battery, and if the short-circuit duration satisfies any one of the following three conditions, terminating the external short-circuit:
condition 1: the short-circuit duration reaches an initially set lossless short-circuit time threshold, wherein the initially set lossless short-circuit time threshold is associated with an initial battery state of charge (SOC);
condition 2: a second current peak appears, and the short-circuit duration reaches a corrected lossless short-circuit time threshold, wherein the corrected lossless short-circuit time threshold is obtained by correcting the initially set lossless short-circuit time threshold on line by using a time at which a second short-circuit current peak of the battery appears; and
condition 3: battery temperature is higher than target temperature; and
estimating a predicted temperature rise when the external short-circuit occurs on the battery, and if a sum of initial temperature and the predicted temperature rise is higher than the target temperature, ending the heating, and starting a battery system; or
if the sum of initial temperature and the predicted temperature rise is lower than the target temperature, conducting external heating by using the external short-circuit of the battery and an external heater together, and after the battery temperature is higher than or equal to the target temperature, ending heating, and starting the battery system, wherein
the corrected lossless short-circuit time threshold is a mean value of the time at which the second current peak appears and the initially set lossless short-circuit time threshold.

### Claim 2 (depends on 1)

The method according to claim 1, wherein a method for determining the initially set lossless short-circuit time threshold comprises: in a laboratory environment, conducting external short-circuit test on the battery, gradually increasing short-circuit duration, repeating multiple times of short circuits in any short-circuit duration, testing battery capacities before and after the short circuits, and using maximum short-circuit duration in which there is no obvious change in battery capacities before and after short circuits as a critical short-circuit time threshold, wherein a battery capacity change whose percentage is lower than a specific threshold value is determined as no obvious change; and
recording critical short-circuit time thresholds in different SOCs, and shifting downward to a safe area by using the critical short-circuit time thresholds as a base, so as to obtain the initially set lossless short-circuit time threshold.

### Claim 3 (depends on 2)

The method according to claim 2, wherein the external short-circuit test on the battery is conducted in different environment temperature and aging states.

### Claim 4 (depends on 3)

A device for implementing the heating method according to claim 3, comprising a low-temperature heating control unit, a short-circuit trigger device, a main control switch K1, an external heating control switch K2, and the external heater, wherein the low-temperature heating control unit is connected to a control end of the short-circuit trigger device, and the low-temperature heating control unit controls the main control switch K1 and the external heating control switch K2; and the main control switch K1 is connected between a positive electrode of the battery and a DC/DC converter, the external heater is arranged on a surface of the battery, one end of the external heater is connected to the positive electrode of the battery, and an other end thereof is connected to the external heating control switch K2,
one end of the external heating control switch K2 is connected to a negative electrode of the battery, and an other end thereof is connected to the external heater; and
two ends of the short-circuit trigger device are respectively connected to the positive electrode and the negative electrode of the battery, and is in parallel with the external heater.

### Claim 5 (depends on 2)

A device for implementing the heating method according to claim 2, comprising a low-temperature heating control unit, a short-circuit trigger device, a main control switch K1, an external heating control switch K2, and the external heater, wherein
the low-temperature heating control unit is connected to a control end of the short-circuit trigger device, and the low-temperature heating control unit controls the main control switch K1 and the external heating control switch K2; and the main control switch K1 is connected between a positive electrode of the battery and a DC/DC converter,
the external heater is arranged on a surface of the battery, one end of the external heater is connected to the positive electrode of the battery, and an other end thereof is connected to the external heating control switch K2;
one end of the external heating control switch K2 is connected to a negative electrode of the battery, and an other end thereof is connected to the external heater; and
two ends of the short-circuit trigger device are respectively connected to the positive electrode and the negative electrode of the battery, and is in parallel with the external heater.

### Claim 6 (depends on 1)

The method according to claim 1, wherein a condition for triggering the large-current external short-circuit for rapid heating of the battery is that the battery temperature is less than a critical temperature threshold and rapid heating is required.

### Claim 7 (depends on 6)

A device for implementing the heating method according to claim 6, comprising a low-temperature heating control unit, a short-circuit trigger device, a main control switch K1, an external heating control switch K2, and the external heater, wherein the low-temperature heating control unit is connected to a control end of the short-circuit trigger device, and the low-temperature heating control unit controls the main control switch K1 and the external heating control switch K2; and the main control switch K1 is connected between a positive electrode of the battery and a DC/DC converter;
the external heater is arranged on a surface of the battery, one end of the external heater is connected to the positive electrode of the battery, and an other end thereof is connected to the external heating control switch K2; one end of the external heating control switch K2 is connected to a negative electrode of the battery, and an other end thereof is connected to the external heater; and two ends of the short-circuit trigger device are respectively connected to the positive electrode and the negative electrode of the battery, and is in parallel with the external heater.

### Claim 8 (depends on 1)

A device for implementing the heating method according to claim 1, comprising a low-temperature heating control unit, a short-circuit trigger device, a main control switch K1, an external heating control switch K2, and the external heater, wherein
the low-temperature heating control unit is connected to a control end of the short-circuit trigger device, and the low-temperature heating control unit controls the main control switch K1 and the external heating control switch K2; and the main control switch K1 is connected between a positive electrode of the battery and a DC/DC converter;
the external heater is arranged on a surface of the battery, one end of the external heater is connected to the positive electrode of the battery, and an other end thereof is connected to the external heating control switch K2;
one end of the external heating control switch K2 is connected to a negative electrode of the battery, and an other end thereof is connected to the external heater; and
two ends of the short-circuit trigger device are respectively connected to the positive electrode and the negative electrode of the battery, and is in parallel with the external heater.

### Claim 9

A device for implementing a rapid, low-temperature self-healing method for a battery, comprising a low-temperature heating control unit, a short-circuit trigger device, a main control switch K1, an external heating control switch K2, and an external heater, wherein
the low-temperature heating control unit is connected to a control end of the short-circuit trigger device, and the low-temperature heating control unit controls the main control switch K1 and the external heating control switch K2; and the main control switch K1 is connected between a positive electrode of the battery and a DC/DC converter;
the external heater is arranged on a surface of the battery, one end of the external heater is connected to the positive electrode of the battery, and an other end thereof is connected to the external heating control switch K2;
one end of the external heating control swatch K2 is connected to a negative electrode of the battery, and an other end thereof is connected to the external heater; and
two ends of the short-circuit trigger device are respectively connected to the positive electrode and the negative electrode of the battery, and is in parallel with the external heater;
wherein a control method of a heating system specifically comprises the following steps:
triggering a large-current external short-circuit for rapid heating of the battery, recording short-circuit duration and a short-circuit current when the external short-circuit occurs on the battery, and if the short-circuit duration satisfies any one of the following three conditions, terminating the external short-circuit:
condition 1: the short-circuit duration reaches an initially set lossless short-circuit time threshold, wherein the initially set lossless short-circuit time threshold is associated with an initial battery state of charge (SOC);
condition 2: a second current peak appears, and the short-circuit duration reaches a corrected lossless short-circuit time threshold, wherein the corrected lossless short-circuit time threshold is obtained by correcting the initially set lossless short-circuit time threshold on line by using a time at which a second short-circuit current peak of the battery appears; and
condition 3: battery temperature is higher than target temperature; and
estimating a predicted temperature rise when the external short-circuit occurs on the battery, and if a sum of initial temperature and the predicted temperature rise is higher than the target temperature, ending the heating, and starting a battery system; or
if the sum of initial temperature and the predicted temperature rise is lower than the target temperature, conducting external heating by using the external short-circuit of the battery and the external heater together, and after the battery temperature is higher than or equal to the target temperature, ending heating, and starting the battery system.

### Claim 10 (depends on 9)

The device according to claim 9, further comprising a Hall sensor H1 and a Hall sensor H2, wherein the Hall sensor H1 is configured to acquire the short-circuit current of the battery, predict heat produced due to a short circuit and a battery temperature rise according to the short-circuit current, and monitor whether the second short-circuit current peak appears; and the Hall sensor H2 is configured to monitor an output current of the battery system.

### Claim 11 (depends on 10)

The device according to claim 10, wherein both the main control switch K1 and the external heating control switch K2 are in an off state, and the short-circuit trigger device is controlled to trigger the external short-circuit of the battery.

### Claim 12 (depends on 11)

The device according to claim 11, wherein the external heating control switch K2 is switched on, and external self-heating is conducted by using the external heater; and after the heating ends, the main control switch K1 is switched on to start the battery system.

### Claim 13 (depends on 9)

The device according to claim 9, wherein the short-circuit trigger device is configured to implement trigger and termination of the external short-circuit of the battery; the short-circuit trigger device is a controllable switch with low contact internal resistance, and the low-temperature heating control unit controls switch-on or switch-off of the short-circuit trigger device through remote control.

### Claim 14 (depends on 13)

The device according to claim 13, wherein both the main control switch K1 and the external heating control switch K2 are in an off state, and the short-circuit trigger device is controlled to trigger the external short-circuit of the battery.

### Claim 15 (depends on 14)

The device according to claim 14, wherein the external heating control switch K2 is switched on, and external self-heating is conducted by using the external heater; and after the heating ends, the main control switch K1 is switched on to start the battery system.

### Claim 16 (depends on 9)

The device according to claim 9, wherein both the main control switch K1 and the external heating control switch K2 are in an off state, and the short-circuit trigger device is controlled to trigger the external short-circuit of the battery.

### Claim 17 (depends on 16)

The device according to claim 16, wherein the external heating control switch K2 is switched on, and external self-heating is conducted by using the external heater; and
after the heating ends, the main control switch K1 is switched on to start the battery system.